New SIDBI Grade A New Batch Starts on Nov 18

    Register

    Question

    Two inlet pipes, each with the same capacity, can fill an empty tank 'A' together in 20 minutes. There is also an outlet pipe that can empty 40% of the tank 'A' in 10 minutes. If we open just one of these inlet pipes and the outlet pipe simultaneously to drain a completely filled tank 'B'—which holds three times the volume of tank 'A'—how long will it take to empty tank 'B'?

    A 150 minutes Correct Answer Incorrect Answer
    B 200 minutes Correct Answer Incorrect Answer
    C 400 minutes Correct Answer Incorrect Answer
    D 100 minutes Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Total time taken by outlet pipe to empty the tank 'A' = 10 X (100/40) = 25 minutes Let the capacity of tank 'A' be 100 units (L.C.M. of 20 minutes and 25 minutes) Total efficiency of two inlet pipes = (100/20) = 5 units/minute Efficiency of one inlet pipe = 2.5 units/minute Efficiency of outlet pipe = (100/25) = - 4 units/minute Combined efficiency of one inlet and one outlet pipe = 2.5 - 4 = - 1.5 (' - ' sign denotes efficiency of outlet pipe is more than the inlet pipe) Capacity of tank 'B' = (100 X 3) = 300 units Required time = (300/1.5) = 200 minutes

    Practice Next

    Relevant for Exams: