Cannot Be True Question Review

In Cannot Be True questions your task is to identify the answer choice that
cannot be true or is most weakened by the information in the argument.
Answers that could be true are incorrect. The stimulus in a Cannot Be True
question rarely contains a conclusion.
For the Fourth Question Family, the following rules apply:
1. Accept the stimulus information and use only it to prove that one of the
answer choices cannot occur.
2. If an answer choice contains information that does not appear directly in
the stimulus or as a combination of items in the stimulus, then that
answer choice could be true, and it is incorrect. The correct answer
choice will directly disagree with the stimulus or a consequence of the
stimulus.
Cannot Be True questions can be worded in a variety of ways, but the gist of
the question type is to show that an answer cannot follow, and this tends to be
executed in three separate ways:
1. Stating that the answer cannot be true or does not follow.
2. Stating that the answer could be true EXCEPT.
3. Stating that the answer choice must be false.
Cannot Be True questions are tricky because the concept of an answer choice
being possibly true and therefore wrong is counterintuitive. When you
encounter a Cannot Be True question, you must mentally prepare yourself to
eliminate answers that could be true or are possible, and select the one answer
choice that cannot be true or is impossible.
In problems that revolve around numbers and percentages, the stimulus will
often supply enough information for you to determine that certain outcomes
must occur. The correct answer then violates this outcome.
In problems featuring conditional statements, many different scenarios can
occur, except the following:
The sufficient condition occurs, and the necessary condition does not
occur.
Thus, when a conditional statement is made in a Cannot Be True question
stimulus, you should actively seek the answer that matches the scenario above.

Two Notable Stimulus Scenarios

Although Cannot Be True questions are not associated with any particular type
of stimulus scenario, two concepts we have discussed appear with some
frequency: numbers and percentages, and conditional relationships. Both areas
can cause confusion, so let’s examine each in more detail:
1. Numbers and Percentages
As detailed in Chapter Fifteen, numbers and percentages can be
confusing when they appear on the LSAT, and the test makers know
how to exploit certain preconceived notions that students bring with
them to the test. In Cannot Be True questions, the stimulus will often
supply enough information for you to determine that certain outcomes
must occur (for example, increasing market share while the overall
market size remains constant results in greater sales). The correct answer
then violates this outcome.
2. Conditional Statements
Many different scenarios can occur in Cannot Be True questions
featuring conditional statements, except the following:
The sufficient condition occurs, and the necessary condition
does not occur.
Thus, when a conditional statement is made in a Cannot Be True
question stimulus, you should actively seek the answer that matches the
scenario above.
Incorrect answers often play upon the possibility that the necessary
condition occurs but the sufficient condition does not occur. Those
scenarios could occur and are thus incorrect.
Take a look at another Cannot Be True question. Please take a moment to
complete the following question:
2. Good students learn more than what their parents and
teachers compel them to learn. This requires that
these students derive pleasure from the satisfaction of
their curiosity, and one cannot experience such
pleasure unless one is capable of concentrating on a
topic so intently that one loses track of one’s own
identity.
If the statements above are true, each of the following
could also be true EXCEPT:
(A) Some people who are capable of becoming so
absorbed in a topic that they lose track of
their own identities are nevertheless
incapable of deriving pleasure from the
satisfaction of their curiosity.
(B) Most good students do not derive pleasure from
the satisfaction of their curiosity.
(C) Many people who derive pleasure simply from
the satisfaction of their curiosity are not good
students.
(D) Some people who are not good students derive
pleasure from losing track of their own
identities.
(E) Most people who are capable of becoming so
absorbed in a topic that they lose track of
their own identities are not good students.
The stimulus in this problem contains a set of interrelated conditional
statements:
GS = good student
LM = learn more than what their parents and teachers compel them to
learn
DP = derive pleasure from the satisfaction of their curiosity
CC = capable of concentrating on a topic so intently that one loses track
of one’s own identity
1. First sentence: GS------------> LM
2. Second sentence, first part: LM----------------> DP
3. Second sentence, second part: DP-------------> CC
Chain of all statements: GS----------> LM---------> DP-----------> CC
Remember, when you encounter Cannot Be True questions featuring
conditional relationships, actively seek the answer that violates the precept that
when the sufficient condition occurs the necessary condition must also occur. In
this problem, that situation is found in answer choice (B).
Answer choice (A): This answer describes a situation where the necessary
condition in the second part of the second sentence occurs and the sufficient
condition does not. Since the occurrence of the necessary condition does not
make the sufficient condition occur, this scenario could happen and this answer
is therefore incorrect. This type of answer is a frequent wrong answer in Cannot
Be True questions featuring conditional relationships.
Answer choice (B): This is the correct answer. The chain of statements in the
stimulus shows that every good student derives pleasure from the satisfaction of
their curiosity. Thus, it cannot be true that “Most good students do not derive
pleasure from the satisfaction of their curiosity.”
Answer choice (C): Like answer choice (A), this answer describes a situation
where the necessary condition occurs and the sufficient condition does not. This
time the scenario references the relationship in the first sentence.
Answer choice (D): The stimulus only offers information about good students;
no information is given about people who are not good students. Accordingly,
we can make no judgment about these individuals, and the answer is incorrect.
Answer choices that offer groups that do not meet the sufficient condition are
also popular wrong answers in Cannot Be True questions featuring conditional
reasoning.
Answer choice (E): Like answer choices (A) and (C), this answer describes a
situation where the necessary condition occurs and the sufficient condition does
not. Unlike those two answers, you must rely on your understanding of the
chain of all statements in order to understand why this answer is possible.
Because the “capable of becoming so absorbed in a topic that they lose track of
their own identities” is the necessary condition for being a good student, it is
possible that most people who meet this condition are still not good students.
Again, avoid Mistaken Reversals!
Overall, Cannot Be True questions appear infrequently but they can be
troublesome because of their unusual information structure. Whenever you
encounter a Cannot question, focus on searching for the answer that does not
follow or the answer that is disproved by the stimulus.

Cannot Be True Questions

Question types that appear infrequently, such as Evaluate the Argument and
Cannot Be True, tend to consume more time because students are not used to
seeing those types of questions.
When the word “cannot” is used in question stems, it is capitalized.
In Cannot Be True questions your task is to identify the answer choice that
cannot be true or is most weakened by the information in the argument.
As discussed in Chapter Three, Cannot Be True questions are the sole member
of the Fourth Question Family. The Fourth Family is very similar to the First
Family with the exception of the bar on the arrow. This bar signifies a
negative—instead of using the information in the stimulus to prove that one of
the answer choices must be true, you must instead prove that one of the answer
choices cannot occur, or that it disagrees with the information in the stimulus.
The following rules apply to the Fourth Question Family:
1. Accept the stimulus information and use only it to prove that one of the
answer choices cannot occur.
2. If an answer choice contains information that does not appear directly in
the stimulus or as a combination of items in the stimulus, then that
answer choice could be true, and it is incorrect. The correct answer
choice will directly disagree with the stimulus or a consequence of the
stimulus.
From an abstract standpoint, Cannot Be True questions can be viewed in two
ways:
1. Polar Opposite Must Be True Questions
Cannot Be True questions are the polar opposite of Must Be True
questions: instead of proving an answer choice, you disprove an answer
choice.
2. Reverse Weaken Questions
The information model of the Third Question Family (Weaken) is an
arrow with a negative pointing up to the stimulus. The Fourth Family
model is the same except that the arrow points down at the answer
choices. From this perspective, Cannot Be True questions are reverse
Weaken questions: use the information in the stimulus to attack one of
the answers.
Both question descriptions are similar, and neither sounds very difficult. In
practice, however, Cannot Be True questions are tricky because the concept of
an answer choice being possibly true and therefore wrong is counterintuitive.
This type of question appears infrequently, but the test makers are savvy and
they know Cannot questions can catch test takers off-guard and consume more
time than the average question. When you encounter a Cannot Be True
question, you must mentally prepare yourself to eliminate answers that could be
true or that are possible, and select the one answer choice that cannot be true or
that is impossible.
Fortunately, the stimuli in Cannot Be True questions rarely contain a conclusion
(just as in Must Be True and Resolve the Paradox questions). Therefore, you
will not need to assess an argument and you can instead focus on the facts at
hand.
Cannot Be True questions are worded in a variety of ways. The gist of the
question type is to show that an answer cannot follow, and this tasks tends to be
expressed in three separate ways:
1. Stating that the answer cannot be true or does not follow.
Question stem examples:
“If the statements above are true, which one of the following
CANNOT be true?”
“The argument can most reasonably be interpreted as an
objection to which one of the following claims?”
“The statements above, if true, most seriously undermine which
one of the following assertions?”
“The information above, if accurate, can best be used as
evidence against which one of the following hypotheses?”
2. Stating that the answer could be true EXCEPT.
This construction is frequently used to convey the Cannot Be True
concept. If the four incorrect answers could be true, then the one
remaining answer must be the opposite, or cannot be true.
Question stem example:
“If all of the claims made above are true, then each of the
following could be true EXCEPT: ”

Evaluate the Argument Question Problem Set & Answer

Evaluate the Argument Question Problem Set
1. Columnist: George Orwell’s book 1984 has
exercised much influence on a great number of
this newspaper’s readers. One thousand readers
were surveyed and asked to name the one book
that had the most influence on their lives. The
book chosen most often was the Bible; 1984
was second.
The answer to which one of the following questions
would most help in evaluating the columnist’s
argument?
(A) How many books had each person surveyed
read?
(B) How many people chose books other than
1984?
(C) How many people read the columnist’s
newspaper?
(D) How many books by George Orwell other than
1984 were chosen?
(E) How many of those surveyed had actually read
the books they chose?
2. Anders: The physical structure of the brain plays an
important role in thinking. So researchers
developing “thinking machines”—computers
that can make decisions based on both common
sense and factual knowledge—should closely
model those machines on the structure of the
brain.
Yang: Important does not mean essential. After all,
no flying machine closely modeled on birds
has worked; workable aircraft are structurally
very different from birds. So thinking machines
closely modeled on the brain are also likely to
fail. In developing a workable thinking
machine, researchers would therefore increase
their chances of success if they focus on the
brain’s function and simply ignore its physical
structure.
In evaluating Yang’s argument it would be most
helpful to know whether
(A) studies of the physical structure of birds
provided information crucial to the
development of workable aircraft
(B) researchers currently working on thinking
machines take all thinking to involve both
common sense and factual knowledge
(C) as much time has been spent trying to develop
a workable thinking machine as had been
spent in developing the first workable aircraft
(D) researchers who specialize in the structure of
the brain are among those who are trying to
develop thinking machines
(E) some flying machines that were not closely
modeled on birds failed to work
Answer Key

Evaluate the Argument Question Type Review

Evaluate the Argument questions ask you to consider the question, statistic, or
piece of information that would best help determine the logical validity of the
argument presented in the stimulus.
Evaluate the Argument questions are a combination of the Second and Third
Families, and as such you should keep the following considerations in mind:
1. In all Second and Third Family questions the information in the stimulus
is suspect, so you should search for the reasoning error present.
2. The answer choices are accepted as given, even if they include
“new” information.
Evaluate the Argument question stems almost always use the word “evaluate”
or a synonym such as “judge” or “assess.”
To determine the correct answer choice on a Evaluate the Argument question,
apply the Variance TestTM by supplying two opposite responses to the question
posed in the answer choice and then analyze how the varying responses affect
the conclusion in the stimulus. If different responses produce different effects on
the conclusion, the answer choice is correct. If different responses do not
produce different effects, the answer choice is incorrect.
The Variance Test should only be applied to Contenders (to determine which
one is correct) or to the answer choice you believe is correct (to confirm your
selection).

The Variance TestTM

Solving Evaluate questions can be difficult. The nature of the answer choices
allow for separate interpretations, and deciding on a single answer can be
challenging. In order to determine the correct answer choice on a Evaluate the
Argument question, apply the Variance TestTM.
The Variance Test consists of supplying two polar opposite responses to the
question posed in the answer choice and then analyzing how the varying
responses affect the conclusion in the stimulus. If different responses produce
different effects on the conclusion, then the answer choice is correct. If different
responses do not produce different effects, then the answer choice is incorrect.
For example, if an Evaluate the Argument answer choice states “What is the
percentage of people who live near a nuclear plant?” look to test the two most
extreme possibilities: first test the response “0%” for its effect on the conclusion
and then test the response “100%” for its effect on the conclusion. If the answer
choice is correct, one of the percentages should strengthen the argument and
one of the percentages should weaken the argument. If the answer choice is
incorrect, neither response will have an effect on the argument.
Of course, the answer choice does not have to be about percentages for the
technique to work; the Variance Test will work regardless of the nature of the
answer choice. Here are some more example answer choices and Variance Test
responses:
If an answer choice asks “Is the pattern permanent?” first test “Yes” as a
response and then test “No” as a response (remember, you must test
opposite answers). If the answer choice is correct, one response should
strengthen the argument and one response should weaken the argument.
If the answer choice is incorrect, neither response will have an effect on
the argument.
If an answer choice asks “Are corporate or environmental interests more
important?” first test “Corporate interests are more important” as a
response and then test “Environmental interests are more important” as a
response. If the answer choice is correct, one response should strengthen
the argument and one response should weaken the argument. If the
answer choice is incorrect, neither response will have an effect on the
argument.
Now we will use an LSAT question to more fully explore how the question
type works and how the correct answer can be determined by the Variance Test.
Please take a moment to complete the following question:
1. Advertisement: Most power hedge trimmers on the market do an adequate job of trimming hedges, but many power hedge trimmers are dangerous to operate and can cause serious injury when used by untrained operators. Bolter Industries’ hedge trimmer has been tested by National Laboratories, the most trusted name in safety testing. So you know, if you buy a Bolter’s, you are buying a power hedge trimmer whose safety is assured.
The answer to which one of the following questions
would be most useful in evaluating the truth of the
conclusion drawn in the advertisement?
(A) Has National Laboratories performed safety
tests on other machines made by Bolter
Industries?
(B) How important to the average buyer of a
power hedge trimmer is safety of operation?
(C) What were the results of National
Laboratories’ tests of Bolter Industries’
hedge trimmer?
(D) Are there safer ways of trimming a hedge than
using a power hedge trimmer?
(E) Does any other power hedge trimmer on the
market do a better job of trimming hedges
than does Bolter Industries’ hedge trimmer?

Evaluate the Argument Questions

Evaluate the Argument questions ask you to consider the question, statistic, or
piece of information that would best help determine the logical validity of the
argument presented in the stimulus. In other words, you must select the answer
choice that decides whether the argument is good or bad.
To better understand this question type, imagine that you are examining an
argument and you have to ask one question that—depending on the answer to
the question—will reveal whether the argument is strong or weak. By this
definition, there must be a flaw in each argument, and your question, if posed
correctly, can reveal that flaw or eliminate the flaw. Please note that you are not
being asked to prove with finality whether the argument is good or bad—rather,
you must simply ask the question that will help best analyze the validity of the
argument. For this reason, Evaluate the Argument questions can be seen as a
combination of a Strengthen and Weaken question: if you ask the best question,
depending on the answer to the question the argument could be seen as strong
or weak.
As mentioned in Chapter Three, this unusual question type is the only question
that does not fall into one of the four question families. Evaluate the Argument
questions are actually a combination of the Second and Third Families, and as
such you should keep the following considerations in mind:
1. In all Second and Third Family questions the information in the stimulus
is suspect, so you should search for the reasoning error present.
2. The answer choices are accepted as given, even if they include
“new” information. Your task is to determine which answer choice
best helps determine the validity of the argument.
Evaluate the Argument question stems almost always use the word “evaluate”
or a synonym such as “judge” or “assess,” but the intent is always identical: the
question stem asks you to identify the piece of information that would be most
helpful in assessing the argument. Question stem examples:
“The answer to which one of the following questions would contribute
most to an evaluation of the argument?”
“Clarification of which one of the following issues would be most
important to an evaluation of the skeptics’ position?”
“Which one of the following would be most important to know in
evaluating the hypothesis in the passage?”
“Which one of the following would it be most relevant to investigate in
evaluating the conclusion of George’s argument?”
“Which one of the following would it be most helpful to know in order
to judge whether what the scientist subsequently learned calls into
question the hypothesis?”
Evaluate the Argument questions (and Cannot Be True questions, which are
covered in the next chapter) appear infrequently on the LSAT, but the
uniqueness of the question type forces students to take a moment to adjust when
they do appear. Some question types, such as Must Be True and Weaken, recur
so frequently that students become used to seeing them and are comfortable
with the process of selecting the correct answer. When a question type appears
rarely, test-takers are often thrown off-balance and lose time and energy reacting
to the question. The makers of the LSAT are well aware of this, and this is the
reason they intersperse different question types in each section (again, imagine
how much easier the LSAT would be if the Logical Reasoning section was
composed of 25 Must Be True questions). One reason we study each type of
question is to help you become as comfortable as possible with the questions
you will encounter on the test, making your reaction time as fast as possible.

Numbers and Percentages Problem Set Answer Key

All answer keys in this book indicate the source of the question by giving the month and year the LSAT
was originally administered, the Logical Reasoning section number, and the question number within that
section. Each LSAT has two Logical Reasoning sections, and so the Section 1 and Section 2 designators
will refer to the first or second Logical Reasoning section in the test, not the physical section number of the
booklet.
Question #1. Flaw-#%. December 2003 LSAT, Section 1, #12. The correct answer choice is (D)
The politician’s argument is that the claims that price increases have averaged less than 3 percent are
wrong, and in support of that position the politician cites several examples of price increases, each of
which is greater than 3 percent. As mentioned in one of the chapter sidebars, “an average is a composite
number, and within the average there can be a significant degree of variation and no single entity need
embody the exact characteristic of the average (for example, the average weight of a 1 pound rock and a
99 pound rock is 50 pounds).” In making the argument, the politician has focused in on several individual
examples while ignoring the fact that an average is a compilation of many different numbers. Answer
choice (D) perfectly captures the essence of this sampling error.
Answer choice (A): The argument does not contain a source or ad hominem attack. Simply stating that a
position is wrong is different than criticizing the character of that person.
Answer choice (B): To properly claim that the economists are wrong does not require showing that they
are not pricing experts, and hence this answer is incorrect
Answer choice (C): The politician attempts to refute the position by providing evidence about large price
increases for certain products. This process, which involves facts, is different than inferring that a claim is
false because it has not been shown to be true. This answer choice would better describe an argument such
as the following: “you have not proven that God exists, so there must be no God.”
Answer choice (D): This is the correct answer. Citing several examples to refute an average is a doomed
strategy.
Answer choice (E): There is no appeal to emotion present; percentages are used to make the argument.
Question #2. Must-#%. December 1995 LSAT, Section 2, #24. The correct answer choice is (E)
The situation in Ditrama is as follows:
Under the federal revenue-sharing plan, each region receives a share of federal revenues equal to
the share of the total population of Ditrama residing in that region, as shown by a yearly
population survey.
Last year, the percentage of federal revenues Korva received for its share decreased somewhat
even though the population survey on which the revenue-sharing was based showed that Korva’s
population had increased.
If the total population of Korva increased but at the same time they experienced a decrease in revenue
allocation, the only possible solution is that the total population of Ditrama increased by more than the
Korva increase. Thus, you must seek an answer that indicates that the total population increased more than
Korva’s population increased. But be careful: this question is one of high difficulty, and the test makers do
not make it easy to spot the correct answer.
Answer choice (A): Either Mitro or Guadar could have a smaller number of residents than Korva.
Answer choice (B): This answer is impossible to prove because we do not have information about the
population growth of Korva in the years prior to the last one.
Answer choice (C): This is the most popular wrong answer choice. The key error is the claim that “Mitro
and Guadar each increased by a percentage that exceeded” Korva’s increase. Although it must be true that
at least one exceeded Korva’s increase, it does not have to be true that both exceeded Korva, as shown by
the following example:

Numbers and Percentages Problem Set

1. Politician: Those economists who claim that consumer price increases have averaged less
than 3 percent over the last year are mistaken. They clearly have not shopped anywhere
recently. Gasoline is up 10 percent over the last year; my auto insurance, 12 percent; newspapers, 15 percent; propane, 13%; bread, 50 percent.
The reasoning in the politician’s argument is most
vulnerable to criticism on the grounds that the
argument
(A) impugns the character of the economists rather
than addressing their arguments
(B) fails to show that the economists mentioned are
not experts in the area of consumer prices
(C) mistakenly infers that something is not true
from the claim that it has not been shown to
be so
(D) uses evidence drawn from a small sample that
may well be unrepresentative
(E) attempts to persuade by making an emotional
appeal
2. Ditrama is a federation made up of three autonomous regions: Korva, Mitro, and Guadar. Under the federal revenue-sharing plan, each region receives a share of federal revenues equal to the share of the total population of Ditrama residing in that region, as shown by a yearly population survey. Last year, the percentage of federal revenues Korva received for its
share decreased somewhat even though the population survey on which the revenue-sharing was based showed that Korva’s population had increased.
If the statements above are true, which one of the
following must also have been shown by the
population survey on which last year’s
revenue-sharing in Ditrama was based?
(A) Of the three regions, Korva had the smallest
number of residents.
(B) The population of Korva grew by a smaller
percentage than it did in previous years.
(C) The populations of Mitro and Guadar each
increased by a percentage that exceeded the
percentage by which the population of
Korva increased.
(D) Of the three regions, Korva’s numerical
increase in population was the smallest.
(E) Korva’s population grew by a smaller
percentage than did the population of at
least one of the other two autonomous
regions.
3. In 1980, Country A had a per capita gross domestic product (GDP) that was $5,000 higher than that of the European Economic Community. By 1990, the difference, when adjusted for inflation, had increased to $6,000. Since a rising per capita GDP indicates a
rising average standard of living, the average of living in Country A must have risen between 1980 and 1990.
Which one of the following is an assumption on
which the argument depends?
(A) Between 1980 and 1990, Country A and the
European Economic Community
experienced the same percentage increase in
population.
(B) Between 1980 and 1990, the average standard
of living in the European Economic
Community fell.
(C) Some member countries of the European
Economic Community had, during the
1980s, a higher average standard of living
than Country A.
(D) The per capita GDP of the European Economic
Community was not lower by more than
$1,000 in 1990 than it had been in 1980.
(E) In 1990, no member country of the European
Economic Community had a per capita GDP
higher than that of Country A.
4. Students from outside the province of Markland, who in any given academic year pay twice as much tuition each as do students from Markland, had accounted for at least two-thirds of the enrollment at Central Markland College. Over the past 10 years academic standards at the college have risen, and the proportion of students who are not Marklanders has dropped to around 40 percent.
Which one of the following can be properly inferred
from the statements above?
(A) If it had not been for the high tuition paid by
students from outside Markland, the college
could not have improved its academic
standards over the past 10 years.
(B) If academic standards had not risen over the
past 10 years, students who are not
Marklanders would still account for at least
two-thirds of the college’s enrollment.
(C) Over the past 10 years, the number of students
from Markland increased and the number of
students from outside Markland decreased.
(D) Over the past 10 years, academic standards at
Central Markland College have risen by
more than academic standards at any other
college in Markland.
(E) If the college’s per capita revenue from tuition
has remained the same, tuition fees have
increased over the past 10 years.

Answer Key

Numbers and Percentages Problem Set

1. Politician: Those economists who claim that consumer price increases have averaged less
than 3 percent over the last year are mistaken. They clearly have not shopped anywhere
recently. Gasoline is up 10 percent over the last year; my auto insurance, 12 percent; newspapers, 15 percent; propane, 13%; bread, 50 percent.
The reasoning in the politician’s argument is most
vulnerable to criticism on the grounds that the
argument
(A) impugns the character of the economists rather
than addressing their arguments
(B) fails to show that the economists mentioned are
not experts in the area of consumer prices
(C) mistakenly infers that something is not true
from the claim that it has not been shown to
be so
(D) uses evidence drawn from a small sample that
may well be unrepresentative
(E) attempts to persuade by making an emotional
appeal
2. Ditrama is a federation made up of three autonomous regions: Korva, Mitro, and Guadar. Under the federal revenue-sharing plan, each region receives a share of federal revenues equal to the share of the total population of Ditrama residing in that region, as shown by a yearly population survey. Last year, the percentage of federal revenues Korva received for its
share decreased somewhat even though the population survey on which the revenue-sharing was based showed that Korva’s population had increased.
If the statements above are true, which one of the
following must also have been shown by the
population survey on which last year’s
revenue-sharing in Ditrama was based?
(A) Of the three regions, Korva had the smallest
number of residents.
(B) The population of Korva grew by a smaller
percentage than it did in previous years.
(C) The populations of Mitro and Guadar each
increased by a percentage that exceeded the
percentage by which the population of
Korva increased.
(D) Of the three regions, Korva’s numerical
increase in population was the smallest.
(E) Korva’s population grew by a smaller
percentage than did the population of at
least one of the other two autonomous
regions.
3. In 1980, Country A had a per capita gross domestic product (GDP) that was $5,000 higher than that of the European Economic Community. By 1990, the difference, when adjusted for inflation, had increased to $6,000. Since a rising per capita GDP indicates a
rising average standard of living, the average of living in Country A must have risen between 1980 and 1990.
Which one of the following is an assumption on
which the argument depends?
(A) Between 1980 and 1990, Country A and the
European Economic Community
experienced the same percentage increase in
population.
(B) Between 1980 and 1990, the average standard
of living in the European Economic
Community fell.
(C) Some member countries of the European
Economic Community had, during the
1980s, a higher average standard of living
than Country A.
(D) The per capita GDP of the European Economic
Community was not lower by more than
$1,000 in 1990 than it had been in 1980.
(E) In 1990, no member country of the European
Economic Community had a per capita GDP
higher than that of Country A.
4. Students from outside the province of Markland, who in any given academic year pay twice as much tuition each as do students from Markland, had accounted for at least two-thirds of the enrollment at Central Markland College. Over the past 10 years academic standards at the college have risen, and the proportion of students who are not Marklanders has dropped to around 40 percent.
Which one of the following can be properly inferred
from the statements above?
(A) If it had not been for the high tuition paid by
students from outside Markland, the college
could not have improved its academic
standards over the past 10 years.
(B) If academic standards had not risen over the
past 10 years, students who are not
Marklanders would still account for at least
two-thirds of the college’s enrollment.
(C) Over the past 10 years, the number of students
from Markland increased and the number of
students from outside Markland decreased.
(D) Over the past 10 years, academic standards at
Central Markland College have risen by
more than academic standards at any other
college in Markland.
(E) If the college’s per capita revenue from tuition
has remained the same, tuition fees have
increased over the past 10 years.

Numbers and Percentages Problem Set

1. Politician: Those economists who claim that consumer price increases have averaged less
than 3 percent over the last year are mistaken. They clearly have not shopped anywhere
recently. Gasoline is up 10 percent over the last year; my auto insurance, 12 percent; newspapers, 15 percent; propane, 13%; bread, 50 percent.
The reasoning in the politician’s argument is most
vulnerable to criticism on the grounds that the
argument
(A) impugns the character of the economists rather
than addressing their arguments
(B) fails to show that the economists mentioned are
not experts in the area of consumer prices
(C) mistakenly infers that something is not true
from the claim that it has not been shown to
be so
(D) uses evidence drawn from a small sample that
may well be unrepresentative
(E) attempts to persuade by making an emotional
appeal
2. Ditrama is a federation made up of three autonomous regions: Korva, Mitro, and Guadar. Under the federal revenue-sharing plan, each region receives a share of federal revenues equal to the share of the total population of Ditrama residing in that region, as shown by a yearly population survey. Last year, the percentage of federal revenues Korva received for its
share decreased somewhat even though the population survey on which the revenue-sharing was based showed that Korva’s population had increased.
If the statements above are true, which one of the
following must also have been shown by the
population survey on which last year’s
revenue-sharing in Ditrama was based?
(A) Of the three regions, Korva had the smallest
number of residents.
(B) The population of Korva grew by a smaller
percentage than it did in previous years.
(C) The populations of Mitro and Guadar each
increased by a percentage that exceeded the
percentage by which the population of
Korva increased.
(D) Of the three regions, Korva’s numerical
increase in population was the smallest.
(E) Korva’s population grew by a smaller
percentage than did the population of at
least one of the other two autonomous
regions.
3. In 1980, Country A had a per capita gross domestic product (GDP) that was $5,000 higher than that of the European Economic Community. By 1990, the difference, when adjusted for inflation, had increased to $6,000. Since a rising per capita GDP indicates a
rising average standard of living, the average of living in Country A must have risen between 1980 and 1990.
Which one of the following is an assumption on
which the argument depends?
(A) Between 1980 and 1990, Country A and the
European Economic Community
experienced the same percentage increase in
population.
(B) Between 1980 and 1990, the average standard
of living in the European Economic
Community fell.
(C) Some member countries of the European
Economic Community had, during the
1980s, a higher average standard of living
than Country A.
(D) The per capita GDP of the European Economic
Community was not lower by more than
$1,000 in 1990 than it had been in 1980.
(E) In 1990, no member country of the European
Economic Community had a per capita GDP
higher than that of Country A.
4. Students from outside the province of Markland, who in any given academic year pay twice as much tuition each as do students from Markland, had accounted for at least two-thirds of the enrollment at Central Markland College. Over the past 10 years academic standards at the college have risen, and the proportion of students who are not Marklanders has dropped to around 40 percent.
Which one of the following can be properly inferred
from the statements above?
(A) If it had not been for the high tuition paid by
students from outside Markland, the college
could not have improved its academic
standards over the past 10 years.
(B) If academic standards had not risen over the
past 10 years, students who are not
Marklanders would still account for at least
two-thirds of the college’s enrollment.
(C) Over the past 10 years, the number of students
from Markland increased and the number of
students from outside Markland decreased.
(D) Over the past 10 years, academic standards at
Central Markland College have risen by
more than academic standards at any other
college in Markland.
(E) If the college’s per capita revenue from tuition
has remained the same, tuition fees have
increased over the past 10 years.

Numbers and Percentages Problem Set

1. Politician: Those economists who claim that consumer price increases have averaged less
than 3 percent over the last year are mistaken. They clearly have not shopped anywhere
recently. Gasoline is up 10 percent over the last year; my auto insurance, 12 percent; newspapers, 15 percent; propane, 13%; bread, 50 percent.
The reasoning in the politician’s argument is most
vulnerable to criticism on the grounds that the
argument
(A) impugns the character of the economists rather
than addressing their arguments
(B) fails to show that the economists mentioned are
not experts in the area of consumer prices
(C) mistakenly infers that something is not true
from the claim that it has not been shown to
be so
(D) uses evidence drawn from a small sample that
may well be unrepresentative
(E) attempts to persuade by making an emotional
appeal
2. Ditrama is a federation made up of three autonomous regions: Korva, Mitro, and Guadar. Under the federal revenue-sharing plan, each region receives a share of federal revenues equal to the share of the total population of Ditrama residing in that region, as shown by a yearly population survey. Last year, the percentage of federal revenues Korva received for its
share decreased somewhat even though the population survey on which the revenue-sharing was based showed that Korva’s population had increased.
If the statements above are true, which one of the
following must also have been shown by the
population survey on which last year’s
revenue-sharing in Ditrama was based?
(A) Of the three regions, Korva had the smallest
number of residents.
(B) The population of Korva grew by a smaller
percentage than it did in previous years.
(C) The populations of Mitro and Guadar each
increased by a percentage that exceeded the
percentage by which the population of
Korva increased.
(D) Of the three regions, Korva’s numerical
increase in population was the smallest.
(E) Korva’s population grew by a smaller
percentage than did the population of at
least one of the other two autonomous
regions.
3. In 1980, Country A had a per capita gross domestic product (GDP) that was $5,000 higher than that of the European Economic Community. By 1990, the difference, when adjusted for inflation, had increased to $6,000. Since a rising per capita GDP indicates a
rising average standard of living, the average of living in Country A must have risen between 1980 and 1990.
Which one of the following is an assumption on
which the argument depends?
(A) Between 1980 and 1990, Country A and the
European Economic Community
experienced the same percentage increase in
population.
(B) Between 1980 and 1990, the average standard
of living in the European Economic
Community fell.
(C) Some member countries of the European
Economic Community had, during the
1980s, a higher average standard of living
than Country A.
(D) The per capita GDP of the European Economic
Community was not lower by more than
$1,000 in 1990 than it had been in 1980.
(E) In 1990, no member country of the European
Economic Community had a per capita GDP
higher than that of Country A.
4. Students from outside the province of Markland, who in any given academic year pay twice as much tuition each as do students from Markland, had accounted for at least two-thirds of the enrollment at Central Markland College. Over the past 10 years academic standards at the college have risen, and the proportion of students who are not Marklanders has dropped to around 40 percent.
Which one of the following can be properly inferred
from the statements above?
(A) If it had not been for the high tuition paid by
students from outside Markland, the college
could not have improved its academic
standards over the past 10 years.
(B) If academic standards had not risen over the
past 10 years, students who are not
Marklanders would still account for at least
two-thirds of the college’s enrollment.
(C) Over the past 10 years, the number of students
from Markland increased and the number of
students from outside Markland decreased.
(D) Over the past 10 years, academic standards at
Central Markland College have risen by
more than academic standards at any other
college in Markland.
(E) If the college’s per capita revenue from tuition
has remained the same, tuition fees have
increased over the past 10 years.

Numbers and Percentages Problem Set

1. Politician: Those economists who claim that consumer price increases have averaged less
than 3 percent over the last year are mistaken. They clearly have not shopped anywhere
recently. Gasoline is up 10 percent over the last year; my auto insurance, 12 percent; newspapers, 15 percent; propane, 13%; bread, 50 percent.
The reasoning in the politician’s argument is most
vulnerable to criticism on the grounds that the
argument
(A) impugns the character of the economists rather
than addressing their arguments
(B) fails to show that the economists mentioned are
not experts in the area of consumer prices
(C) mistakenly infers that something is not true
from the claim that it has not been shown to
be so
(D) uses evidence drawn from a small sample that
may well be unrepresentative
(E) attempts to persuade by making an emotional
appeal
2. Ditrama is a federation made up of three autonomous regions: Korva, Mitro, and Guadar. Under the federal revenue-sharing plan, each region receives a share of federal revenues equal to the share of the total population of Ditrama residing in that region, as shown by a yearly population survey. Last year, the percentage of federal revenues Korva received for its
share decreased somewhat even though the population survey on which the revenue-sharing was based showed that Korva’s population had increased.
If the statements above are true, which one of the
following must also have been shown by the
population survey on which last year’s
revenue-sharing in Ditrama was based?
(A) Of the three regions, Korva had the smallest
number of residents.
(B) The population of Korva grew by a smaller
percentage than it did in previous years.
(C) The populations of Mitro and Guadar each
increased by a percentage that exceeded the
percentage by which the population of
Korva increased.
(D) Of the three regions, Korva’s numerical
increase in population was the smallest.
(E) Korva’s population grew by a smaller
percentage than did the population of at
least one of the other two autonomous
regions.
3. In 1980, Country A had a per capita gross domestic product (GDP) that was $5,000 higher than that of the European Economic Community. By 1990, the difference, when adjusted for inflation, had increased to $6,000. Since a rising per capita GDP indicates a
rising average standard of living, the average of living in Country A must have risen between 1980 and 1990.
Which one of the following is an assumption on
which the argument depends?
(A) Between 1980 and 1990, Country A and the
European Economic Community
experienced the same percentage increase in
population.
(B) Between 1980 and 1990, the average standard
of living in the European Economic
Community fell.
(C) Some member countries of the European
Economic Community had, during the
1980s, a higher average standard of living
than Country A.
(D) The per capita GDP of the European Economic
Community was not lower by more than
$1,000 in 1990 than it had been in 1980.
(E) In 1990, no member country of the European
Economic Community had a per capita GDP
higher than that of Country A.
4. Students from outside the province of Markland, who in any given academic year pay twice as much tuition each as do students from Markland, had accounted for at least two-thirds of the enrollment at Central Markland College. Over the past 10 years academic standards at the college have risen, and the proportion of students who are not Marklanders has dropped to around 40 percent.
Which one of the following can be properly inferred
from the statements above?
(A) If it had not been for the high tuition paid by
students from outside Markland, the college
could not have improved its academic
standards over the past 10 years.
(B) If academic standards had not risen over the
past 10 years, students who are not
Marklanders would still account for at least
two-thirds of the college’s enrollment.
(C) Over the past 10 years, the number of students
from Markland increased and the number of
students from outside Markland decreased.
(D) Over the past 10 years, academic standards at
Central Markland College have risen by
more than academic standards at any other
college in Markland.
(E) If the college’s per capita revenue from tuition
has remained the same, tuition fees have
increased over the past 10 years.

Numbers and Percentages Review

The makers of the LSAT often prey upon several widely-held misconceptions:
Misconception #1: Increasing percentages automatically lead to
increasing numbers.
Misconception #2: Decreasing percentages automatically lead to
decreasing numbers.
Misconception #3: Increasing numbers automatically lead to increasing
percentages.
Misconception #4: Decreasing numbers automatically lead to decreasing
percentages.
Misconception #5: Large numbers automatically mean large
percentages, and small numbers automatically mean
small percentages.
Misconception #6: Large percentages automatically mean large
numbers, and small percentages automatically mean
small numbers.
Words that introduce numerical ideas:
Amount
Quantity
Sum
Total
Count
Tally
Words that introduce percentage ideas:
Percent
Proportion
Fraction
Ratio
Incidence
Likelihood
Probability
Segment
Share
Use the following general rules for Must Be True questions:
1. If the stimulus contains percentage or proportion information only, avoid
answers that contain hard numbers.
2. If the stimulus contains only numerical information, avoid answers that
contain percentage or proportion information.
3. If the stimulus contains both percentage and numerical information, any
answer choice that contains numbers, percentages, or both may be true.
Use the following general rules for Weaken and Strengthen questions:
To weaken or strengthen an argument containing numbers and
percentages, look carefully for information about the total amount(s)—
does the argument make an assumption based on one of the
misconceptions discussed earlier?
Market share is simply the portion of a market that a company controls. Market
share can be measured either in terms of revenues (sales) or units sold.
Regardless of the size of a market, total market share must always add up to
100%.

Markets and Market Share

The makers of the LSAT expect you to understand the operation of markets and
the concept of market share. Market operation includes supply and demand,
production, pricing, and profit. None of these concepts should be unfamiliar to
you as they are a part of everyday life.
Market share is simply the portion of a market that a company controls. The
market share can be measured either in terms of revenues (sales) or units sold.
For example:
Heinz has a 60% market share of the $500 million ketchup market.
Jif brand peanut butter sold 80 million units last year, a 30% market share.
Because market share is a numbers and percentages concept, market share can
change when factors in the market change. For example, a company can gain
market share (percentage) if the market shrinks and they maintain a constant
size, or if they grow in an unchanging market. However, a company losing
market share does not mean that their sales decreased, only that they became a
smaller entity in the market relative to the whole (the market grew and they
stayed the same size, for example). Similarly, a company could lose sales and
still gain market share if the overall market became smaller.
Regardless of the size of a market and even though the total amount of the
market can shift, the total market share must always add up to 100%.
Please take a moment to complete the following question:
1. Rumored declines in automobile-industry revenues are exaggerated. It is true that automobile manufacturers’ share of the industry’s revenues fell from 65 percent two years ago to 50 percent today, but over the same period suppliers of automobile parts had their share increase from 15 percent to 2 percent and service companies (for example, distributors, dealers, and repairers) had their share increase from 20 percent to 30 percent.
Which one of the following best indicates why the
statistics given above provide by themselves no
evidence for the conclusion they are intended to
support?
(A) The possibility is left open that the statistics
for manufacturers’ share of revenues come
from a different source than the other
statistics.
(B) No matter what changes the automobile
industry’s overall revenues undergo, the
total of all shares of these revenues must be
100 percent.
(C) No explanation is given for why the revenue
shares of different sectors of the industry
changed.
(D) Manufacturers and parts companies depend for
their revenue on dealers’ success in selling
cars.
(E) Revenues are an important factor but are not
the only factor in determining profits.
The conclusion of the argument states that the rumored declines in automobileindustry
revenues are exaggerated (a numerical statement), but the premises
provided in support of this argument only address the market share percentages
of the three groups that have automobile-industry revenues (percentage
statements). The percentage statements used by the author only indicates that
the percentages have changed, not whether overall revenue has changed:

Numbers and Percentages

Similar to Cause and Effect Reasoning, Conditional Reasoning, and Formal
Logic, the concept of Numbers and Percentages is featured in many LSAT
stimuli. Although most people are comfortable working with numbers or
percentages because they come up so frequently in daily life (for example in
balancing a checking account, dividing a bar tab, or adding up a grocery bill),
the makers of the LSAT often prey upon several widely-held misconceptions:
Misconception #1: Increasing percentages automatically lead to
increasing numbers.
Most people assume that if a percentage becomes larger, the number that
corresponds to that percentage must also get larger. This is not
necessarily true because the overall size of the group under discussion
could get smaller. For example, consider the following argument: “Auto
manufacturer X increased their United States market share from 10%
last year to 25% this year. Therefore, Company X sold more cars in the
United States this year than last.” This is true if the size of the U.S. car
market stayed the same or became larger. But if the size of the U.S. car
market decreased by enough, the argument would not be true, as in the
following example:
                              Last Year            This Year
Total number of cars                   1000              200
sold in the United States
X’s market share                       10%               25%
X’s total car sales                      100               50
in the United States
Thus, even though auto manufacturer X’s market share increased to
25%, because the size of the entire market decreased significantly, X
actually sold fewer cars in the United States.
Misconception #2: Decreasing percentages automatically lead to
decreasing numbers.
This misconception is the opposite of Misconception #1. Just because a
percentage decreases does not necessarily mean that the corresponding
number must become smaller. Reversing the years in the previous
example proves this point.
Misconception #3: Increasing numbers automatically lead to increasing
percentages.
Just as increasing percentages do not automatically translate into
increasing numbers, the reverse is also true. Consider the following
example: “The number of bicycle-related accidents rose dramatically
from last month to this month. Therefore, bicycle-related accidents must
make up a greater percentage of all road accidents this month.” This
conclusion can be true, but it does not have to be true, as shown by the
following example:
                        Last Month          This Month
Number of bicycle-related            10              30
accidents
Total number of road accidents        100             600
Percentage of total accidents          10%             5%
that are bicycle-related
Thus, even though the number of bicycle-related accidents tripled, the
percentage of total road accidents that were bicycle-related dropped
because the total number of road accidents rose so dramatically.
Misconception #4: Decreasing numbers automatically lead to decreasing
percentages.
This misconception is the opposite of Misconception #3. Just because a
number decreases does not necessarily mean that the corresponding
percentage must become smaller. Reversing the months in the previous
example proves this point.
Misconception #5: Large numbers automatically mean large
percentages, and small numbers automatically mean
small percentages.
In 2003, Porsche sold just over 18,000 cars in the United States. While
18,000 is certainly a large number, it represented only about 1/5 of 1%
of total U.S. car sales in 2003. Remember, the size of a number does not
reveal anything about the percentage that number represents unless you
know something about the size of the overall total that number is drawn
from.
Misconception #6: Large percentages automatically mean large
numbers, and small percentages automatically mean
small numbers.
This misconception is the reverse of Misconception #5. A figure such as
90% sounds impressively large, but if you have 90% of $5, that really
isn’t too impressive, is it?
Numerical situations normally hinge on three elements: an overall total, a
number within that total, and a percentage within the total. LSAT problems will
often give you one of the elements, but without at least two elements present,
you cannot make a definitive judgment about what is occurring with another
element. When you are given just percentage information, you cannot make a
judgment about numbers. Likewise, when you are given just numerical
information you cannot make a judgement about percentages.
In a moment, we will explore this idea by examining several LSAT questions.
But first, you must be able to recognize number and percentage ideas when they
appear on the LSAT:
Words used to introduce numerical ideas:
Amount
Quantity
Sum
Total
Count
Tally
Words used to introduce percentage ideas:
Percent
Proportion
Fraction
Ratio
Incidence
Likelihood
Probability
Segment
Share
Three words on the percentage list—“incidence, “likelihood,” and
“probability”—bear further discussion. Each of these words relates to the
chances that an event will occur, and when the LSAT makers uses phrases such
as “more likely” or “less likely” they are telling you that the percentage chances
are greater than 50% or less than 50%, respectively. In fact, a wide variety of
phrases can be used to introduce percentage ideas, including such disparate
phrases as “more prone to” or “occurs with a high frequency.”
With these indicators in mind, please take a moment to complete the following
question:
1. From 1973 to 1989 total energy use in this country increased less than 10 percent. However, the use of energy in this country during this same period grew by more than 50 percent, as did the gross national product—the total value of all goods and services produced in the nation.
If the statements above are true, then which one of
the following must also be true?
(A) Most of the energy used in this country in
1989 was electrical energy.
(B) From 1973 to 1989 there was a decline in the
use of energy other than electrical energy in
this country.
(C) From 1973 to 1989 there was an increase in
the proportion of energy use in this country
that consisted of electrical energy use.
(D) In 1989 electrical energy constituted a larger
proportion of the energy used to produce the
gross national product than did any other
form of energy.
(E) In 1973 the electrical energy that was
produced constituted a smaller proportion of
the gross national product than did all other
forms of energy combined.
Like the vast majority of Must Be True problems, the stimulus does not contain
a conclusion. We are given the following facts, however:
From 1973 to 1989 total energy use increased less than 10%.
During this same period, the use of electrical energy grew by more than
50%.
During this same period, the gross national product (GNP) grew by
more than 50%.
A careful examination of the second sentence reveals that there is no stated
connection between the growth of the GNP and the increase in the use of
electrical energy. If you assume that the use of electrical energy somehow
caused the growth of the GNP, you are guilty of making an unwarranted causal
assumption. Because there is no stated connection between the two other than
they both grew by more than 50%, any answer that attempts to connect the two
is incorrect. Answer choices (D) and (E) can both be eliminated by this
reasoning.
Now that we recognize that the GNP issue is only a red herring, let us examine
the percentages that are given in the stimulus. The 50% increase in electrical
energy gives the impression that the jump must have been substantial. But we
know from Misconception #6 that a large percentage does not automatically
mean a large number. For example, in this problem it is possible that the 50%
increase in electrical energy use was a jump from 2 units to 3 units. The
possibility that electrical energy use in 1973 was a relatively small percentage of
overall energy use directly undermines answer choices (A), as shown by the
following example:
                          1973               1989
Total energy use                 100              109
(in units)
Electrical energy use                10              15
(in units)
Percentage of total energy             10%           13+%
use that was electrical
A close analysis of the chart also reveals that answer choice (B) can be
eliminated. In the example, the use of energy other than electrical energy rose
from 90 units to 94 units.
Although the example disproves both answer choice (A) and (B), obviously
you do not have time to make a chart during the test to examine each possibility,
so is there a faster way to eliminate the first two answers? Yes—consider the
previous discussion point that information about percentages does not tell us
about the numbers. With that idea in mind, because the stimulus contains only
percentage information (even though there are two percentages), you should be
very suspicious of answer choice (A) (which states that the number of electrical
units used was greater) and answer choice (B) (which states that the use of nonelectrical
energy declined) since they both contain numerical information. At the
same time, you should be attracted to an answer such as (C) because it contains
only percentage information, and as it turns out, answer choice (C) is correct.
Because the misconceptions discussed earlier have a predictable effect when
you try to make inferences, you can use the following general rules for Must Be
True questions:
1. If the stimulus contains percentage or proportion information only, avoid
answers that contain hard numbers.
Example Stimulus Sentence:
The car market share of Company X declined this year.
Avoid answers which say:
Company X sold a smaller number of cars this year.
Company X sold a greater amount of cars this year.
2. If the stimulus contains only numerical information, avoid answers that
contain percentage or proportion information.
Example Stimulus Sentence:
Company Y sold fewer computers this year.
Avoid answers which say:
Company Y now has a lower share of the computer market.
Company Y now possesses a greater proportion of the
computer market.
3. If the stimulus contains both percentage and numerical information, any
answer choice that contains numbers, percentages, or both may be true.
Please keep in mind that these rules are very general. You must read the
stimulus closely and carefully to determine exactly what information is present
because the makers of the LSAT are experts at camouflaging or obscuring
important information in order to test your ability to understand complex
argumentation.
Please take a moment to complete the following question:
2. The number of North American children who are
obese—that is, who have more body fat than do 85
percent of North American children their age—is
steadily increasing, according to four major studies
conducted over the past 15 years.
If the finding reported above is correct, it can be
properly concluded that
(A) when four major studies all produce similar
results, those studies must be accurate
(B) North American children have been
progressively less physically active over the
past 15 years
(C) the number of North American children who
are not obese increased over the past 15
years
(D) over the past 15 years, the number of North
American children who are underweight has
declined
(E) the incidence of obesity in North American
children tends to increase as the children
grow older
Like the previous question, this is a Must Be True question with a stimulus that
does not contain a conclusion. But, this stimulus does provide information about
both the numbers and percentages of obese children, and so you can end up
with an answer that has either a number or a percentage (though a numerical
answer is more likely since the percentage is fixed at a constant 15% in the
stimulus).

Parallel Reasoning Question Problem Set & Answer Key

Parallel Reasoning Question Problem Set Answer Key
1. The student body at this university takes courses in a wide range of disciplines. Miriam is a student at this university, so she takes courses in a wide range of disciplines.
Which one of the following arguments exhibits
flawed reasoning most similar to that exhibited by
the argument above?
(A) The students at this school take mathematics.
Miguel is a student at this school, so he takes
mathematics.
(B) The editorial board of this law journal has
written on many legal issues. Louise is on the
editorial board, so she has written on many
legal issues.
(C) The component parts of bulldozers are heavy.
This machine is a bulldozer, so it is heavy.
(D) All older automobiles need frequent oil
changes. This car is new, so its oil need not
be changed as frequently.
(E) The individual cells of the brain are incapable
of thinking. Therefore, the brain as a whole is
incapable of thinking.
2. Commentator: Because of teacher hiring freezes, the quality of education in that country will not improve. Thus, it will surely deteriorate.
The flawed reasoning in which one of the following
is most similar to that in the commentator’s
argument?
(A) Because Raoul is a vegetarian, he will not have
the pepperoni pizza for lunch. It follows that
he will have the cheese pizza.
(B) Given that over 250 years of attempts to prove
the Goldbach conjecture have failed, it will
probably never be proved. Hence, it is more
likely to be disproved than proved.
(C) Since funding levels for social programs are
being frozen, our society will not become
more harmonious. Thus, it may become more
discordant.
(D) Since there is a storm moving in, the outside
temperature cannot rise this afternoon.
Therefore, it must fall.
(E) The starter in Mary’s car gave out weeks ago,
and so it is impossible for the car to start.
Therefore, it will not start.
3. Most people who shop for groceries no more than three times a month buy prepared frozen dinners regularly. In Hallstown most people shop for groceries no more than three times a month. Therefore, in Hallstown most people buy prepared frozen dinners regularly.
Which one of the following arguments has a flawed
pattern of reasoning most like the flawed reasoning
in the argument above?
(A) It is clear that most drivers in West Ansland are
safe drivers since there are very few driving
accidents in West Ansland and most
accidents there are not serious.
(B) It is clear that John cannot drive, since he does
not own a car and no one in his family who
does not own a car can drive.
(C) It is clear that Fernando’s friends usually drive
to school, since all of his friends can drive
and all of his friends go to school.
(D) It is clear that most people in Highland County
drive sedans, since most people who
commute to work drive sedans and most
people in Highland County commute to
work.
(E) It is clear that most of Janine’s friends are good
drivers, since she accepts rides only from
good drivers and she accepts rides from most
of her friends.
4. Bank deposits are credited on the date of the transaction only when they are made before 3 P.M. Alicia knows that the bank deposit was made before 3 P.M. So, Alicia knows that the bank deposit was credited on the date of the transaction.
Which one of the following exhibits both of the
logical flaws exhibited by the argument above?
(A) Journalists are the only ones who will be
permitted to ask questions at the press
conference. Since Marjorie is a journalist, she
will be permitted to ask questions.
(B) We know that Patrice works only on Thursday.
Today is Thursday, so it follows that Patrice
is working today.
(C) It is clear that George knows he will be
promoted to shift supervisor, because George
will be promoted to shift supervisor only if
Helen resigns, and George knows Helen will
resign.
(D) John believes that 4 is a prime number and that
4 is divisible by 2. Hence John believes that
there is a prime number divisible by 2.
(E) Pat wants to become a social worker. It is well
known that social workers are poorly paid.
Pat apparently wants to be poorly paid.
Parallel Reasoning Question Problem Set Answer Key

Parallel Reasoning Question Review

Parallel Reasoning questions ask you to identify the answer choice that contains
reasoning most similar in structure to the reasoning in the stimulus.
Parallel Flaw questions are Parallel Reasoning questions where the stimulus
contains flawed reasoning.
The question stem for any Parallel question reveals whether the stimulus
contains valid or invalid reasoning. If the question stem mentions a flaw, then
the reasoning is invalid. If the question stem does not mention a flaw, then the
reasoning is valid.
The following elements do not need to be paralleled:
1. Topic of the stimulus
2. The order of presentation of the premises and conclusion in the stimulus
Instead, you must parallel all of these elements:
1. The Method of Reasoning
2. The Validity of the Argument
3. The Conclusion
4. The Premises
Because each element must be matched, you can analyze and attack the answer
choices by testing whether the answer choice under consideration matches
certain elements in the stimulus. If not, the answer is incorrect. The following
list outlines the four tests you can use to evaluate answers, in rough order of
how useful they are:
1. Match the Method of Reasoning
2. Match the Conclusion
3. Match the Premises
4. Match the Validity of the Argument
If all else fails, create a short statement that summarizes the “action” in the
argument. Then, take the abstraction and compare it to each argument. Does it
match your generalized version of the stimulus? If not, the answer is incorrect.

Solving Parallel Reasoning Questions

Because you must find the answer with a similar pattern of reasoning to that in
the stimulus, using the details of the stimulus to attack the answer choices works
differently in Parallel Reasoning question than in other First Family questions.
For example, The Fact Test plays a minimal role in Parallel questions because
the details (topic, etc.) of the stimulus and each answer choice are different.
Instead, the structural basis of these questions forces you to compare the bigpicture
elements of the argument: intent of the conclusion, force and use of the
premises, the relationship of the premises and the conclusion, and the soundness
of the argument. Comparing these elements is like using an Abstract Fact Test—
you must examine the general features of the argument in the answer choice and
match them to the argument in the stimulus.
First, let us examine the elements of an argument that do not need to be
paralleled in these questions:
1. Topic of the stimulus
In Parallel Reasoning questions, the topic or subject matter in the
stimulus and the answer choices is irrelevant because you are looking
for the argument that has a similar pattern of reasoning. Often, samesubject
answer choices are used to attract the student who fails to focus
on the reasoning in the stimulus. For example, if the topic of the
stimulus is banking, you need not have an answer choice that is also
about banking.
2. The order of presentation of the premises and conclusion in the stimulus
The order of presentation of the premises and conclusion in the stimulus
is also irrelevant. As long as an answer choice contains the same general
parts as the stimulus, they need not be in the same order because the
order of presentation does not affect the logical relationship that
underlies the pieces. So, for example, if the stimulus has an order of
conclusion-premise-premise, you need not have the same order in the
correct answer.
Neither of the elements above has any bearing on the correctness of an answer
choice. Now, let’s look at the elements that must be paralleled, and how to use
these elements to eliminate wrong answer choices:
1. The Method of Reasoning
It may sound obvious, but the type of reasoning used in the stimulus
must be paralleled. When you see an identifiable form of reasoning
present—for example, causal reasoning or conditional reasoning—you
can proceed quickly and look for the answer that matches the form of
the stimulus. Given the numerous forms of reasoning we have examined
(both valid and invalid), you now have a powerful arsenal of knowledge
that you can use to attack these questions. First and foremost, if you
recognize the form of reasoning used in the stimulus, immediately attack
the answers and search for the answer with similar reasoning.
2. The Validity of the Argument
The validity of the reasoning in the correct answer choice must match
the validity of the reasoning in the stimulus.
Often, answer choices can be eliminated because they contain reasoning
that has a different logical force than the stimulus. If the stimulus
contains valid reasoning, eliminate any answer choice that contains
invalid reasoning. If the stimulus contains invalid reasoning, eliminate
any answer choice that contains valid reasoning.
3. The Conclusion
Every Parallel Reasoning stimulus contains an argument and therefore a
conclusion. Because your job is to parallel the argument, you must
parallel the subcomponents, including the premises and conclusion. You
can use this knowledge to attack specific answer choices: if an answer
has a conclusion that does not “match” the conclusion in the stimulus,
then the answer is incorrect. Using this approach is especially helpful if
you do not see an identifiable form of reasoning in the stimulus.
When matching conclusions, you must match the certainty level or
intent of the conclusion in the stimulus, not necessarily the specific
wording of the conclusion. For example, a stimulus conclusion
containing absolutes (“must,” “never,” “always”) will be matched by a
conclusion in the correct answer choice using similar absolutes; a
stimulus conclusion that gives an opinion (“should”) will be matched by
the same idea in the correct answer choice; a conditional conclusion in
the stimulus will be matched by a conditional conclusion in the correct
answer choice, and so on. This knowledge allows you to quickly
narrow down the answer choices to the most likely candidates. This
advice can initially be confusing, so let us discuss it in more detail.
Contenders (assuming there is no other reason to knock them out of
contention). Identical wording for our purposes means answers where
the controlling modifiers (such as “must,” “could,” “many,” “some,”
“never,” etcetera) are the same. For example, if the conclusion of the
argument stated, “The reactor can supply the city power grid,” an
answer that had similar wording, such as “The bank can meet the needs
of customers,” would be a Contender. In brief, the advice in this
paragraph is fairly simple: if the conclusion in the answer choice has
similar wording to the conclusion in the stimulus, then the answer is
possibly correct.
Second, because there are many synonyms available for the test makers
to use, do not eliminate answers just because the wording is not
identical. For example, an answer could state, “The majority of voters
endorsed the amendment.” The quantity indicator in the sentence—
“majority”—has several synonyms, such as “most” and “more than
half.” Make sure that when you examine each sentence that you do not
eliminate an answer that has wording that is functionally identical to the
wording in the stimulus.
Third, remember that the English language has many pairs of natural
opposites, so the presence of a negative term in the stimulus is not
grounds for dismissing the answer when the stimulus has positive
language (and vice versa). For example, a conclusion could state, “The
councilmember must be present at the meeting.” That conclusion could
just as easily have been worded as, “The councilmember must not be
absent from the meeting.” In the same way, an answer choice can use
opposite language (including negatives) but still have a meaning that is
similar to the stimulus.
If the stimulus has a positive conclusion, then the presence of negative
terms in the conclusion is not grounds for eliminating the answer; if the
stimulus has a negative conclusion, then the lack of a negative term in
the conclusion is not grounds for eliminating the answer.
4. The Premises
Like the conclusion, the premises in the correct answer choice must
match the premises in the stimulus, and the same wording rules that
were discussed in The Conclusion section apply to the premises.
Matching premises is a step to take after you have checked the
conclusion, unless you notice that one (or more) of the premises has an
unusual role in the argument. If so, you can immediately look at the
answer choices and compare premises.
Because the four components above must be paralleled in the correct answer
choice, the test makers have an array of options for making an answer incorrect.
They can create answer choices that match several of the elements but not all of
the elements, and to work through each answer choice in traditional fashion can
be a painstaking process. However, since each element must be matched, you
can analyze and attack the answer choices by testing whether the answer choice
under consideration matches certain elements in the stimulus. If not, the answer
is incorrect.
Upon hearing this advice, most students say, “Sounds good. In what order
should I examine at the elements?” Although the process can be reduced to a
step-by-step procedure, a better approach is to realize that examining the
elements is like a waterfall and that everything will happen very quickly.
Performing well on the LSAT is about flexibility and correctly responding to the
clues provided. Rigidly applying the methods below will rob you of the
opportunity to accelerate through the problem. Therefore, in Parallel Reasoning
questions your job is to identify the features of the argument most likely to be
“points of separation”—those features that can be used to divide answers into
Losers and Contenders. Sometimes matching the conclusion will knock out
several answer choices, other times matching the premises will achieve that
same goal. The following list outlines the four tests you can use to evaluate
answers, in rough order of their usefulness:
1. Match the Method of Reasoning
If you identify an obvious form of reasoning (use of analogy, circular
reasoning, conditional reasoning, etc.), move quickly to the answer
choices and look for the answer with an identical form of reasoning.
2. Match the Conclusion
If you cannot identify the form of reasoning, or if you still have two or
more answer choices in contention after matching the reasoning, or if
the conclusion seems to have unusual language, examine the conclusion
of each answer choice and match it against the conclusion in the
stimulus. Matching the conclusion can be a critical time-saver because it
often eliminates one or more answers. On occasion, all five conclusions
in the answer choices will be identical to that in the stimulus. That is not
a problem—it just means that the other elements must be used to knock
out the wrong answers.
The key to successfully matching the conclusion is that you must be
able to quickly pick out the conclusion in each answer choice. This is
where the conclusion identification skills discussed in Chapter Two
come into play.
3. Match the Premises
If matching the method of reasoning and conclusion does not eliminate
the four wrong answer choices, try matching the premises. The more
complex the argument structure in the stimulus, the more likely you will
have to match the premises to arrive at the correct answer. The less
complex the argument, the more likely that matching the conclusion will
be effective.
4. Match the Validity of the Argument
Always make sure to eliminate any answer choice that does not match
the logical force (valid or invalid) of the argument. This test rarely
eliminates all four answers, but it can often eliminate one or two answer
choices.
Now practice applying these elements. Please take a moment to complete the
following problem:

The Peril of Abstraction

Parallel Reasoning questions force you to evaluate six different arguments.
Parallel Reasoning questions are challenging because they are the most abstract
type of question on the LSAT. Not only must you understand the structure of
the argument in the stimulus, you must also understand the structure of the
arguments in each of the five answer choices. Juggling all this abstract
information is difficult, and you will learn how to effectively approach Parallel
Reasoning questions in the following pages.
We will address several effective ways to handle the abstract nature of these
questions, but first you must understand what approach not to take. Some
companies recommend that you make general abstract diagrams for the
elements in each stimulus and do the same for each answer choice. This
“general symbolization” approach involves representing the premises and
conclusion as “A,” “B,” “C,” etcetera, and writing them next to the stimulus.
This approach, while well-meaning, is hopelessly flawed. Parallel Reasoning
questions are difficult because they involve a great deal of abstraction. The use
of non-specific symbols such as “A,” “B,” and “C” further abstracts the stimulus
elements, increasing the difficulty instead of alleviating it.
Please note that the method described above is different than the symbolization
described in the conditional reasoning and causal reasoning chapters of this
book. In those chapters, we recommend diagramming in response to specific
logical formations, and we strongly recommend using symbols that directly
represent elements in the stimulus. That approach, when properly used, makes
the questions easier to attack.

Parallel Flaw Questions

If the reasoning is flawed, the question stem will state that the reasoning is bad
by using words such as “flawed” or “questionable.” If the reasoning is not flawed, then
the question stem will not refer to flawed reasoning.
The stimulus for a Parallel Reasoning question can contain either valid or
invalid reasoning. Since the February 1992 LSAT, whenever a Parallel
Reasoning question contains flawed reasoning, it is stated in the question stem.
If there is no mention of flawed reasoning in the question stem, the reasoning in
the stimulus is valid (and vice versa).When a Parallel Reasoning stimulus contains
flawed reasoning, we identify it as
a Parallel Flaw question. Like Flaw in the Reasoning questions, Parallel Flaw
questions use many of the common forms of erroneous reasoning.
Here are two Parallel Flaw question stem examples. They are virtually identical
to the previous Parallel Reasoning questions stems with the exception that they
contain a term indicating that the reasoning in the stimulus is invalid:
“The flawed reasoning in which one of the following is most similar to
the flawed reasoning in the argument above?”
“The questionable pattern of reasoning in the argument is most similar to
that in which one of the following?”

Parallel Reasoning Questions

Parallel Reasoning questions ask you to identify the answer choice that contains
reasoning most similar in structure to the reasoning in the stimulus. Since this
task requires you to first identify the method of argumentation used by the
author and then to match that reasoning to the reasoning presented in each
answer choice, these questions can be quite time consuming (a fact known to
and exploited by the test makers).
Like Method of Reasoning and Flaw in the Reasoning questions, Parallel
Reasoning questions are in the First Family and have the same information
structure. However, because of the abstract nature of these questions, comparing
the stimulus to the answer choices takes on a different dimension, and we will
address this issue in a moment in the section entitled Solving Parallel Reasoning
Questions.
Question stem examples:
“Which one of the following is most closely parallel in its reasoning to
the reasoning in the argument above?”
“Which one of the following exhibits a pattern of reasoning most similar
to that exhibited by the argument above?”
“Which one of the following arguments is most similar in its logical
features to the argument above?”
“Which one of the following arguments is most similar in its pattern of
reasoning to the argument above?”
“The structure of the reasoning in the argument above is most parallel to
that in which one of the following?”

Flaw in the Reasoning Question Problem Set Answer Key

All answer keys in this book indicate the source of the question by giving the month and year the LSAT
was originally administered, the Logical Reasoning section number, and the question number within that
section. Each LSAT has two Logical Reasoning sections, and so the Section 1 and Section 2 designators
will refer to the first or second Logical Reasoning section in the test, not the physical section number of the
booklet.
Question #1. Flaw. October 2000 LSAT, Section 2, #6. The correct answer choice is (C)
As with all Flaw in the Reasoning questions, you must closely examine the relationship between the
premises and the conclusion. In this argument, the editorial concludes that the advice of the economic
advisor is untrustworthy and “the premier should discard any hope of reducing taxes without a significant
decrease in government services.” What support is offered for this position? Is a discussion of taxation
issued presented? Is a discussion of the cost of government service provided? Is the position of the
economic advisor dissected? No. According to the editorial, the only reason for ignoring the economic
advisor’s advice is that the advisor was convicted in his youth of embezzlement. This fact has no bearing
on the argument made by the advisor, and focuses instead on attacking the person making the argument.
This is a classic Source or ad hominem argument, and you should immediately seek an answer choice that
reflects this fact.
Answer choice (A): A proposal is not rejected in the stimulus; rather, a goal is advocated by the advisor
and then the author questions whether that goal can be met by examining the background of the advisor.
There is no discussion of a “particular implementation” that is likely to fail.
Answer choice (B): This answer fails the Fact Test because there is no discussion of “what could happen
otherwise” and no discussion of people’s fears.
Answer choice (C): This is the correct answer. The answer is a perfect description of a Source argument.
Answer choice (D): This answer describes an evidence error in which a lack of evidence for a position is
considered to hurt the claim. In the argument, the author improperly used evidence about the advisor, and
this mistake is the error in the argument. Even though this introduced a flaw into the argument, from the
author’s perspective this was an attempt to use evidence against a position to hurt the position. The
editorial did not state or indicate that there was a lack of evidence when forming the conclusion. Put
simply, the editor thought he had a reason that undermined the claim; no argument was made that there
was a lack of evidence.
Answer choice (E): This answer describes Circular Reasoning. But, because the argument in the stimulus
gives reasons for its position (albeit weak ones), the argument is not circular.
Question #2. Flaw. December 2001 LSAT, Section 1, #10. The correct answer choice is (C)
As always, look closely at the structure of the argument—specifically the relationships between the
premises and conclusion. This breakdown presents the pieces in the order given in the argument:
Conclusion: Cotrell is, at best, able to write magazine articles of average quality.
Subconclusion/
Premise: The most compelling pieces of evidence for this are those few of the numerous articles
submitted by Cotrell that are superior.
Premise: Cotrell, who is incapable of writing an article that is better than average, must obviously
have plagiarized superior ones.
Examine the language in the conclusion (“Cotrell is, at best, able to write magazine articles of average
quality”) and the premise (“Cotrell, who is incapable of writing an article that is better than average”). The
two are identical in meaning, and thus we have an argument with circular reasoning. Do not be distracted
by the plagiarism argument in the middle of the text—that is a tool used to physically separate the
conclusion and premise, making it harder to recognize that the two are identical.
Answer choice (A): The argument does not ignore the potential counterevidence to the conclusion. The
potential counterevidence is the few articles submitted by Cotrell that are superior, and the author dismisses
them by claiming they are plagiarized. Although the reasoning used to dismiss the good articles is flawed,
it is an attempt to address the evidence, and thus the argument cannot be said to “simply ignore the
existence of potential counterevidence.”
Answer choice (B): This answer choice describes an Overgeneralization. The answer is wrong because
the argument generalizes by dismissing the atypical occurrences (the superior articles), as opposed to
generalizing from them.
Answer choice (C): This is the correct answer, and one of several different ways to describe Circular
Reasoning (note that in the first problem in this set Circular Reasoning was an incorrect answer). More
often than not, when you see Circular Reasoning it will be an incorrect answer choice, but you cannot be
complacent and simply assume it will be wrong every time you see it. This problem proves that it does
appear as the correct answer on occasion.
Answer choice (D): This answer describes an Appeal to Authority. The answer fails the Fact Test because
there is no reference to the judgment of experts.
Answer choice (E): This answer is similar to answer choice (B). The answer starts out reasonably well—
“it infers limits on ability.” The argument does attempt this (depending on your definition of “infer”). But,
does the argument make this inference based on a “few isolated lapses in performance?” No, the argument
dismisses the few superior performances. In this sense the answer is Half Right, Half Wrong. Therefore, it
is incorrect.
Question #3. Flaw. October 2002 LSAT, Section 1, #23. The correct answer choice is (A)
The structure of the argument is as follows:
Premise: Food producers irradiate food in order to prolong its shelf life.
Premise: Five animal studies were recently conducted to investigate whether this process alters
food in a way that could be dangerous to people who eat it. The studies concluded that
irradiated food is safe for humans to eat.
Premise: These studies were subsequently found by a panel of independent scientists to be
seriously flawed in their methodology.
Conclusion: Irradiated food is not safe for human consumption.
The author uses the fact that the studies were flawed to conclude that irradiated food is not safe for human
consumption. Is this a reasonable conclusion? No. The studies purported to prove that irradiated food is
safe. The fact that the studies used flawed methodology should have been used to prove that the studies
did not prove that irradiated food was safe. Instead, the activist takes the argument too far, believing that
because the studies did not prove that irradiated food is safe, therefore irradiated food is not safe. This is
the third errorin the Errors in the Use of Evidence section, where “Some evidence against a position is
taken to prove that position is false.” Answer choice (A) perfectly describes this mistake.
Answer choice (B): Use the Fact Test to easily eliminate this answer. Although past studies were shown to
have methodological flaws, this evidence is not used to prove that methodologically sound alternatives are
impossible to achieve.
Answer choice (C): It’s true, the argument does fail to consider the possibility that a non-flawed study
might provide only weak support for its conclusion. But—and this is the critical question—is that a flaw in
the reasoning of the activist? No, it is perfectly acceptable for the author to ignore an issue (non-flawed
studies) that does not relate to his argument. Remember, the correct answer choice must describe a flaw in
the reasoning of the argument, not just something that occurred in the argument.
Answer choice (D): As with answer choice (C), the author has failed to consider the statement in this
answer choice. But is this a flaw? No. The fact that animal testing is widely done and the results are
accepted as indicative of possible problems with humans falls under the “commonsense information”
discussed back in Chapter Two. Testing products on animals is a current fact of life, and the author made a
reasoning error by failing to consider the possibility that what is safe for animals might not always be safe
for human beings.
Another way of looking at this answer is that it effectively states that the author has failed to consider that
there is a False Analogy between animals and humans. He fails to consider it because the analogy between
animals and humans is not false.
Answer choice (E): Again, the activist does fail to establish this, but it is not necessary since the
independent scientists only commented on the methodology of the study, not the irradiated food itself.
Question #4. Flaw. October 2001 LSAT, Section 2, #18. The correct answer choice is (B)
This argument contains an error of composition, one where the status-enhancing activities of most
scientists are said to prove that the scientific community as a whole acts to enhance its status.
Answer choice (A): This answer choice describes a compositional error, but not the one that occurs in the
stimulus. The stimulus makes a judgment about the scientific community as a whole whereas this answer
states that a judgment is made about each and every scientist. The community as a whole is different than
each and every scientist, and thus this answer is incorrect.
If you are thinking about the difference between the community as a whole and each member within the
community, consider this statement: “Our community is against stealing.” While that may be true, there
may also be individual members of the community who are thieves and have no qualm about stealing.
Answer choice (B): This is the correct answer, and the answer describes the correct compositional error
made by the philosopher.
Answer choice (C): The answer is wrong—the author does not presume that the aim of personal career
enhancement never advances the pursuit of truth. Consider the second sentence: “Accordingly, the
professional activities of most scientists are directed toward personal career enhancement, and only
incidentally toward the pursuit of truth. The portion that states “only incidentally toward the pursuit of
truth” indicates that the author allows for the possibility that career-enhancement activities can result in
activities that pursue truth, even if only a little bit. But, since that contradicts the force of never, this answer
is incorrect.
This is the most frequently chosen wrong answer, as about 20% of test takers select this choice.
Answer choice (D): This answer choice describes the Uncertain Use of a Term. The term “self-interested”
is used only once in the argument (at the end of the first sentence), and the remainder of the argument is
consistent with the generally accepted meaning of “self-interested” and uses that meaning unambiguously.
Answer choice (E): The argument in the stimulus is about the relationships of parts and wholes, not about
cause and effect. This answer, which describes reasoning from an effect in order to infer its cause, is
therefore incorrect. An example of the reasoning described in this answer choice would be: “We know this
window was broken this afternoon, and only one pane of the window was broken. We also know the pane
was broken by a circular object. Therefore, a baseball was the cause of the broken window.