Question

    Pipe A alone can fill 75% of a cistern in 18 minutes.

    When both Pipe A and Pipe B are opened together, they can fill the entire cistern in 33 minutes. How long would it take for Pipe B alone to empty the full cistern?
    A 96 min Correct Answer Incorrect Answer
    B 90 min Correct Answer Incorrect Answer
    C 72 min Correct Answer Incorrect Answer
    D 88 min Correct Answer Incorrect Answer

    Solution

    Time taken by pipe 'A' alone to completely fill the cistern = 18 ÷ 0.75 = 24 minutes
    So, let the capacity of the cistern = L.C.M of 24 and 33 = 264 units
    So, efficiency of pipe of 'A' = 264 ÷ 24 = 11 units/minute
    Combined efficiency of pipes 'A' and 'B' = 264 ÷ 33 = 8 units/minute
    So, efficiency of pipe 'B' alone = 8 - 11 = 3 units/minute (outlet)
    So, time taken by pipe 'B' alone to empty the cistern = 264 ÷ 3 = 88 minutes

    Practice Next
    More Time and work Questions

    Relevant for Exams:

    ask-question