Question

A is thrice as good a workman as B and therefore is able to finish a job in 60 days less than
B. Working together, they can do it in:

A 12.5 days Correct Answer Incorrect Answer
B 22.5 days Correct Answer Incorrect Answer
C 18.2 days Correct Answer Incorrect Answer
D 28 days Correct Answer Incorrect Answer

Solution

Efficiency Ratio A : B = 3 : 1 Time Ratio A : B = 1 : 3 Difference in time units = 3 - 1 = 2 units. Given difference = 60 days. So, 2 units = 60 => 1 unit = 30 days. A takes 30 days (1 unit). B takes 90 days (3 units). Together = (A × B) / (A + B) = (30 × 90) / (30 + 90) = 2700 / 120 = 22.5 days.

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