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%.