Official Guide Explanation:
Problem Solving #138

Background

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Solution and Metadata

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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