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## Official Guide Explanation:Data Sufficiency #6

Background

This is just one of hundreds of free explanations I've created to the quantitative questions in The Official Guide for GMAT Quantitative Review (2nd 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: 6
Page: 153
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Ratio and Proportion >
Category 2: Algebra > Linear Equations-Two Unk >

Explanation: Here we're looking for the value of x + y.

Statement (1) is insufficient; it tells us that y = x + 5. We can't get from that equation to the value of x + y.

Statement (2) is also insufficient. It gives us a ratio; if it takes Ann 6 weeks to save what Beth saves in 5 weeks, Beth saves (6/5) as much as Ann does. In algebraic form, that's y = (6/5)x.

Taken together, the statements are sufficient. We have two linear equations with two variables. We don't need to find the value of x + y, just recognize that we can. Choice (C) is correct.

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