Question

    A and B working together, can do a piece of work in 4(1/2) hours. B and C working together can do it in 3 hours. C and A working together can do it in 2(1/4) hours. All of them begin the work at the same time. Find how much time they will take to finish the piece of work?

    A 3 hours Correct Answer Incorrect Answer
    B 2 hours Correct Answer Incorrect Answer
    C 2.5 hours Correct Answer Incorrect Answer
    D 1 hour Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    AB = 9/2 BC = 3 CA = 9/4 Efficiency of AB : BC : CA = 2 : 3 : 4 LCM (Total units) = 36 Now, 2(A + B + C) = 2 (2 + 3 + 4) = 18 To finish the work they will take = 36/18 = 2 hours

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