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## Official Guide Explanation:Problem Solving #138

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: 138
Page: 171
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Fractions >
Category 2: Word Problems > Rate Problems > other

Explanation: Given the number of unknown values this question starts out with (the number of workers on each shift and the number of boxes for each worker), it's a great question to assign numbers to those unknowns. Say that each worker on the day shift loads 4 boxes, which means that each worker on the night shift loads 3 ((3/4) of 4). If the day crew has 5 workers, then the night crew has (4/5)(5) = 4 workers. Thus, the day crew loaded a total of 4(5) = 20 boxes, while the night crew loaded 3(4) = 12 boxes, for a total of 32 boxes. Of that total, the day crew loaded (20/32) = (5/8), choice (E).

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