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    Question

    There are three taps of diameter 2 cm, 3 cm and 4 cm,

    respectively. The ratio of the water flowing through them is equal to the ratio of the square of their diameters. The biggest tap can fill an empty tank alone in 81 min. If all the taps are opened simultaneously, then how long will the tank take (in min) to be filled?
    A 34(20/29) Correct Answer Incorrect Answer
    B 64(20/29) Correct Answer Incorrect Answer
    C 54(20/29) Correct Answer Incorrect Answer
    D 44(20/29) Correct Answer Incorrect Answer

    Solution

    The ratio of efficiencies = (2)2 : (3)2 : (4)2= 4 : 9 : 16.  Given The biggest tap can fill the tank alone in 81 min So, Total work = 16 x 81  Total efficiency = 4 + 9 + 16 = 29. Then Total Time =(total work / Total efficiency ) = (16 × 81) / 29 = 44 (20/29)

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