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## Official Guide Explanation:Data Sufficiency #77

Background

This is just one of hundreds of free explanations I've created to the quantitative questions in The Official Guide for GMAT Review (12th ed.). Click the links on the question number, difficulty level, and categories to find explanations for other problems.

These are the same explanations that are featured in my "Guides to the Official Guide" PDF booklets. However, because of the limitations of HTML and cross-browser compatibility, some mathematical concepts, such as fractions and roots, do not display as clearly online.

Question: 77
Page: 279
Difficulty: 5 (Moderate)
Category 1: Word Problems > Other >
Category 2: Arithmetic > Percents > other

Explanation: This is a concept that the GMAT repeatedly tests. The salesman's compensation can be representated as follows, where s is his sales:

300 + 0.05(s - 1000)

Statement (1) is sufficient. We know that his compensation is equal to 10% of his sales, so we can set that equal to the other way we can express his compensation:

0.1s = 300 + 0.05(s - 1000)

0.1s = 300 + 0.05s - 50

0.05s = 250

s = 5000

Once we know his sales, we can calculate his compensation.

Statement (2) is also sufficient. Given his sales and the expression derived from the question, we can calculate his compensation:

300 + 0.05(s - 1000)

300 + 0.05(5000 - 1000)

300 + 0.05(4000)

300 + 200 = 500

Choice (D) is correct.

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