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## Official Guide Explanation:Data Sufficiency #61

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: 61
Page: 157
Difficulty: 5 (Moderate)
Category 1: Algebra > Linear Equations-Two Unk >
Category 2: Algebra > Equations >

Explanation: 2x(5n) = 10xn, so to find t, you must be able to find the value of xn. Statement (1) is insufficient: between the initial equation and the equation in this statement, you have two equations with three variables. Statement (2) is also insufficient: plug in 32 for x, and you still need the value of n to solve for t.

Taken together, the statements are sufficient. There are three linear equations (10xn = t, x = n + 3, and 2x = 32), and three variables (t, n, and x), so you can solve for any of the variables, including t. Choice (C) is correct.

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