Question

    P, Q and R three pipes connected to a tank. P and Q together fill the tank in 30 hours, Q and R together fill the tank in 40 hours. P and R together fill the tank in 60 hours. In how much time will P, Q and R fill the tank separately?

    A 80, 60, 120 Correct Answer Incorrect Answer
    B 60, 120, 240 Correct Answer Incorrect Answer
    C 80, 48, 240 Correct Answer Incorrect Answer
    D 80, 60, 240 Correct Answer Incorrect Answer

    Solution

    A + B fill in 30 hrs B + C fill in 40 hrs A + C fill in 60 hrs 2(A + B + C) fill in (30× 40× 60) ÷ (30× 40 + 40× 60 + 60× 30) = 40/3 hours Therefore A + B + C fill the tank in 80/3 hours Now, A = (A + B + C) – (B + C) fills in (3/80 - 1/40) = 1/80 = 80 hours Similarly B fills in (3/80 - 1/60) = 1/24 = 48 hours And C fills in (3/80 - 1/30) = 1/240 = 240 hours.

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