Official Guide Explanation:
Problem Solving #126




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Solution and Metadata

Question: 126
Page: 170
Difficulty: 5 (Moderate)
Category 1: Word Problems > Work Problems > 2 inputs
Category 2: Arithmetic > Fractions >

Explanation: In "combined work" problems, use the following equation: ((ab)/(a + b)), where a and b are the rates of each of the individual entities doing work independently. Plug in 3 and 4 as the question indicates: ((3(4))/(3 + 4)) = (12/7) = 1(5/7), choice (C).

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