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    Question

    In what time would a Cistern be filled by three pipes

    whose diameter are 2cm, 2 2/3cm and 4cm running together, where the largest pipe alone fill it in 183 minutes. The amount of water flowing in by each pipe being proportional to the square of diameter?
    A 72 minutes Correct Answer Incorrect Answer
    B 110 minutes Correct Answer Incorrect Answer
    C 140 minutes Correct Answer Incorrect Answer
    D 206 minutes Correct Answer Incorrect Answer
    E 108 minutes Correct Answer Incorrect Answer

    Solution

    ATQ,

    Flow rates are proportional to the square of the diameter:

    Total combined flow rate:

    Cistern capacity (from Pipe 3 alone) = 16 × 183 = 2928

    Time to fill with all pipes together:

    Therefore, the cistern will be filled in 108 minutes.

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