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## Official Guide Explanation:Data Sufficiency #30

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: 30
Page: 155
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Real Numbers >
Category 2: Algebra > Linear Equations-Two Unk >

Explanation: Statement (1) is sufficient. r, s, t, and u all must be between 1 and 9, since they are nonzero digits. The only set of nonzero digits that fulfills the equation r = 3s = 2t = 6u is r = 6, s = 2, t = 3, and u = 1, so x = 0.6231. Statement (2) is not sufficient: if ru = st, there are many possibilities, including the one that works in (1) as well as r = 2, u = 3, s = 1, and t = 6. Choice (A) is correct.

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