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    Question

    A and B together, B and C together and A and C

    together can complete a piece of work in 88 days, 66 days and 72 days respectively. Find the ratio of the efficiencies of A, B and C, respectively.
    A 4:5:7 Correct Answer Incorrect Answer
    B 4:3:7 Correct Answer Incorrect Answer
    C 4:7:5 Correct Answer Incorrect Answer
    D 7:5:4 Correct Answer Incorrect Answer
    E 4:2:7 Correct Answer Incorrect Answer

    Solution

    Let, the total work be 792 units (LCM of 88, 66 and 72)
    Amount of work done by A and B together in one day = 792/88 = 9 units
    Amount of work done by B and C together in one day = 792/66 = 12 units
    Amount of work done by A and C together in one day = 792/72 = 11 units
    Amount of work done by A, B and C together in one day = (9 + 12 + 11)/2 = 16 units
    Amount of work done by A alone in one day = 16 – 12 = 4 units
    Amount of work done by B alone in one day = 16 – 11 = 5 units
    Amount of work done by C alone in one day = 16 – 9 = 7 units
    So the desired ratio = 4:5:7

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