Three pumps, P, R, and T, working simultaneously at their respective constant rates, can fill a tank in 5 hours. Pumps P and R,

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问题 Three pumps, P, R, and T, working simultaneously at their respective constant rates, can fill a tank in 5 hours. Pumps P and R, working simultaneously at their respective constant rates, can fill the tank in 7 hours. How many hours will it take pump T, working alone at its constant rate, to fill the tank?

选项 A、1.7
B、10.0
C、15.0
D、17.5
E、30.0

答案D

解析 Working simultaneously, pumps P and R fill 1/7 of the tank in 1 hour. Working simultaneously, the three pumps fill 1/5 of the tank in 1 hour. Therefore, working alone, pump T fills, or 2/35, of the tank in 1 hour. Thus, working alone, pump T takes 35/2 hours, or 17.5 hours, to fill the tank. The correct answer is Choice D.
This explanation uses the following strategies.
Strategy 1: Translate from Words to an Arithmetic or Algebraic Representation
Strategy 8: Search for a Mathematical Relationship
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本试题收录于: GRE QUANTITATIVE题库GRE分类
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