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    Question

    A and B together can complete a piece of work in 12

    days. A alone can complete the work in 20 days. A starts the work and is joined by B after 5 days. How many more days will they take to complete the remaining work?
    A 6 days Correct Answer Incorrect Answer
    B 8 days Correct Answer Incorrect Answer
    C 7 days Correct Answer Incorrect Answer
    D 9 days Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Total work = LCM of 12 and 20 = 60 units. Efficiency of A = 60 ÷ 20 = 3 units/day. Efficiency of A and B together = 60 ÷ 12 = 5 units/day. Work done by A in 5 days = 5 × 3 = 15 units. Remaining work = 60 - 15 = 45 units. Time taken by A and B together to complete remaining work = 45 ÷ 5 = 9 days. Correct Option: d) 9 days

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