Question

    A and B together can complete a piece of

    work in 42 days while B and C together can complete the same work in 50 days. All of three together can complete 80% of the whole work in 26.4 days then find the time taken by A and C together to complete the whole work. Note: You have to find approx. value
    A 52 days Correct Answer Incorrect Answer
    B 57 days Correct Answer Incorrect Answer
    C 50 days Correct Answer Incorrect Answer
    D 44 days Correct Answer Incorrect Answer
    E 60 days Correct Answer Incorrect Answer

    Solution

    Time taken by A, B and C together to complete the whole work = 26.4/0.80 = 33 days
    Let total amount of work = 11550 (LCM of 42, 50 and 33)
    Efficiency of (A + B) = 11550/42 = 275 units per day
    Efficiency of (B + C) = 11550/50 = 231 units per day
    Efficiency of (A + B + C) = 11550/33 = 350 units per day
    Efficiency of A = 350 – 231 = 119 units per day
    Efficiency of C = 350 – 275 = 75 units per day
    Desired time = 11550/194 = 59.5 days = 60 days

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