Question

    P alone can finish a piece of work ‘M’ in 5 days

    while Q takes 3 days to finish it alone. P, Q and R working together can finish the work ‘N’ which is 11 times of work ‘M’ in 5 days. How long will R take to finish work ‘N’, when working alone?
    A 6.6 days Correct Answer Incorrect Answer
    B 5 days Correct Answer Incorrect Answer
    C 8 days Correct Answer Incorrect Answer
    D 12 days Correct Answer Incorrect Answer
    E 15 days Correct Answer Incorrect Answer

    Solution

     Let the work ‘M’ = 15 units (LCM of 5 and 3) Efficiency of P = 15/5 = 3 units Efficiency of Q = 15/3 = 5 units Efficiency of P, Q and R = (15 × 11)/5 = 33 units per day Efficiency of R = 33 – (3 + 5) = 25 units per day Time taken by R to finish work ‘N’ = 165/25 = 6.6 days

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