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    Question

    Tap P can fill a water tank in 15 minutes, Tap Q can

    fill it in 20 minutes, and Tap R can empty half of the tank in 15 minutes. Now, if all the taps, P, Q, and R, are opened simultaneously, with the unique ability that Tap R starts to empty the tank after the first minute, how long will it take to completely fill the water tank
    A 15 min 36 seconds Correct Answer Incorrect Answer
    B 25 min 36 seconds Correct Answer Incorrect Answer
    C 11 minutes 36 seconds Correct Answer Incorrect Answer
    D 10 min 36 seconds Correct Answer Incorrect Answer
    E none of these Correct Answer Incorrect Answer

    Solution

    ATQ,

    Taps P and Q fill the tank in the first minute:

    After 1 minute, Taps P, Q, and R work together:

    Remaining work = 1 - 7/60 = 53/60

    Time to complete remaining work =(53/60)/(1/12) = 10.6 minutes Total time = 1minute + 10.6minutes = 11 minutes 36 seconds.

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