Official Guide Explanation:
Problem Solving #120




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Solution and Metadata

Question: 120
Page: 77
Difficulty: 6 (Moderately Difficult)
Category 1: Word Problems > Other >
Category 2: Arithmetic > Percents > other

Explanation: This is a convoluted question. Faced with a lot of complexity, try to break it down to smaller parts. Say that the number of trucks rented out is t. Thus, before any trucks were returned, there were 20 - t trucks on the lot. Then, when half of the trucks were returned, the number of trucks on the lot was 20 - t + 0.5t = 20 - 0.5t. If that number is at least 12, we can set up an equation and solve for t:

20 - 0.5t ≥ 12

8 ≥ 0.5t

16 ≥ t

If t is less than or equal to 16, then the greatest number of trucks that could have been rented out is 16, choice (B).

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