Question

    Pipe A and B can fill the pool in 30 minutes and 40 minutes, respectively. Pipe C can empty half filled pool in 30 minutes. If all the pipes are opened together, then find the time taken to fill the empty pool completely

    A 20 minutes Correct Answer Incorrect Answer
    B 27 minutes Correct Answer Incorrect Answer
    C 28 minutes Correct Answer Incorrect Answer
    D 24 minutes Correct Answer Incorrect Answer

    Solution

    Time taken by pipe C to empty the full pool = 30 × 2 = 60 minutes Let the capacity of pool = 120 units Number of units of water filled by pipe A alone in one minute = 120/30 = 4 units Number of units of water filled by pipe B alone in one minute = 120/40 = 3 units Number of units of water emptied by pipe C alone in one minute = 120/60 = 2 units Required time taken = 120/(4 + 3 – 2) = 24 minutes

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