Question

‘A’ and ‘B’ can do a piece of work in 20 days and 32 days, respectively. If they started the work together and worked on it for 9 days, then find the time taken by ‘B’ alone to complete the remaining work.

A 8.5 days Correct Answer Incorrect Answer
B 7.6 days Correct Answer Incorrect Answer
C 8.4 days Correct Answer Incorrect Answer
D 8.6 days Correct Answer Incorrect Answer

Solution

Let total amount of work be 160 units  Efficiency of ‘A’ = 160/20 = 8 units/day Efficiency of ‘B’ = 160/32 = 5 units/day Amount of work done by ‘A’ and ‘B’ together in 9 days = (8 + 5) × 9 = 117 units Time taken by B to complete remaining work = (160 – 117)/5 = 8.6 days

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