Question

    Pipe ‘A’ can fill a tank in 16 hours. Pipe ‘B’

    is ____% as efficient as pipe ‘A’. If both pipes are opened simultaneously, the tank will be completely full in ____hours.The values given in which of the following options will fill the blanks in the same order in which is it given to make the statement true: I. 60, 10II. 75, 8.5III. 140, 7
    A Only I Correct Answer Incorrect Answer
    B Only I and II Correct Answer Incorrect Answer
    C All I, II and III Correct Answer Incorrect Answer
    D Only I and III Correct Answer Incorrect Answer
    E Only III Correct Answer Incorrect Answer

    Solution

    Let the capacity of the tank be ‘80x’ litres.

    So, efficiency of pipe ‘A’ = 80x ÷ 16 = ‘5x’ litres/hour

    For: I

    Efficiency of pipe ‘B’ = 5x × 0.60 = ‘3x’ litres/hour

    Time taken by both pipes together to fill the tank = 80x ÷ (3x + 5x) = 10 hours

    Therefore, statement ‘I’ is true.

    For: II

    Efficiency of pipe ‘B’ = 5x × 0.75 = 3.75x litres/hour

    Time taken by both pipes together to fill the tank = 80x ÷ (3.75x + 5x) ~ 9.14 hours

    Therefore, statement ‘II’ is not true.

    For: III

    Efficiency of pipe ‘B’ = 5x × 1.4 = 7x litres/hour

    Time taken by both pipes together to fill the tank = 80x ÷ (7x + 5x) ~ 6.66 hours

    Therefore, statement ‘III’ is not true.

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