New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    P alone can finish a piece of work ‘M’ in 6 days

    while Q takes 3 days to finish it alone. P, Q and R working together can finish the work ‘N’ which is 12 times of work ‘M’ in 6 days. How long will R take to finish work ‘N’, when working alone?
    A 8 days Correct Answer Incorrect Answer
    B 15 days Correct Answer Incorrect Answer
    C 10 days Correct Answer Incorrect Answer
    D 12 days Correct Answer Incorrect Answer
    E 6 days Correct Answer Incorrect Answer

    Solution

     Let the work ‘M’ = 6 units (LCM of 6 and 3) Efficiency of P = 6/6 = 1 units Efficiency of Q = 6/3 = 2 units Efficiency of P, Q and R = (6 × 12)/6 = 12 units per day Efficiency of R = 12 – (1 + 2) = 9 units per day Time taken by R to finish work ‘N’ = 72/9 = 8 days

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