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## Official Guide Explanation:Problem Solving #183

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: 183
Page: 178
Difficulty: 5 (Moderate)
Category 1: Word Problems > Rate Problems > Speed
Category 2: Arithmetic > Percents > Percent Change

Explanation: The most straightforward way to find the answer to this question is to start by finding car X's rate. r = ((d)/(t)) = (80/2) = 40. 50% faster than 40 miles per hour is 40 + (0.5)(40) = 40 + 20 = 60, so car Y traveled at 60 miles per hour. Now solve for car Y's time:

60 = (80/(t))

60t = 80

t = (80/60)

t = 1(1/3), choice (C).

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