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## Official Guide Explanation:Problem Solving #37

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: 37
Page: 66
Difficulty: 4 (Moderately Easy)
Category 1: Word Problems > Rate Problems > other
Category 2: Arithmetic > Ratio and Proportion >

Explanation: To get the maximum mileage on 15 gallons of gasoline, the car needs to get its best mileage, 22.4 miles per gallon. To solve for the number of miles, set up a miles per gallon ratio: 22.4 = ((x)/15). To solve: x = 15(22.4). The question asks you to approximate, so do so: start with 15(20) = 300, then 15(2) = 30, so 15(22.4) must be at least 330, and only choice (A) is greater, so it must be correct.

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