Question

    108 unit of work can be completed by P alone in 18 days.

    P started working alone and joined by Q after 9 days such that they completed the remaining work in 3 days. Find the number of days taken by Q to complete the whole work alone.
    A 9 days Correct Answer Incorrect Answer
    B 30 days Correct Answer Incorrect Answer
    C 22 days Correct Answer Incorrect Answer
    D 37.5 days Correct Answer Incorrect Answer
    E 38 days Correct Answer Incorrect Answer

    Solution

    Let the efficiency of Q = x units/day Efficiency of P = (108/18) = 6 units/day According to question: 6 × 9 + (6 + x) × 3 = 108 Or, 54 + 18 + 3x = 108 Or, 3x = 108 – 72 Or, 3x = 36 Or, x = 12 Number of days taken by Q to complete the work alone = (108/12) = 9 days

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