New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    Two pipes A and B can fill a tank in 12 hours and 16

    hours, respectively. A third pipe C can empty the tank in 24 hours. If all three pipes are opened together, how long will it take to fill the tank?
    A 8 hours Correct Answer Incorrect Answer
    B 9.6 hours Correct Answer Incorrect Answer
    C 10.5 hours Correct Answer Incorrect Answer
    D 12 hours Correct Answer Incorrect Answer

    Solution

    Work done by A in 1 hour = 1/12. Work done by B in 1 hour = 1/16. Work done by C in 1 hour = −1/24. Net work done in 1 hour = 1/12 + 1/16 − 1/24. LCM of 12, 16, and 24 is 48. Net work done in 1 hour = (4 + 3 − 2)/48 = 5/48. Time taken to fill the tank = 48/5 = 9.6 hours. Ans. b

    Practice Next