Official Guide Explanation:
Data Sufficiency #37

Background

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Solution and Metadata

Question: 37
Page: 276
Difficulty: 4 (Moderately Easy)
Category 1: Word Problems > Other >
Category 2: Arithmetic > Percents > other

Explanation: If we use the first letter of "selling price," "cost," and "markup," we can express the first sentence as follows:

s = c + m

We want to know what percent the markup is of the selling price, or:

((m)/(s)) * 100%

Statement (1) is sufficient. If the markup is 25% of the cost, the cost is 4 times the markup, or 4m. Thus:

s = c + m

s = 4m + m = 5m

If s = 5m, then ((m)/(s)) * 100 = ((m)/(5m)) * 100% = 20%.

Statement (2) is insufficient. It gives us one number, but no way to determine relationships between any two of the three amounts. Choice (A) is correct.

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