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Railways Sample Paper RRB (Group D) Sample Test Paper-4

  • question_answer
    A tap can empty a tank in 30 minutes. A second tap can empty it in 45 minutes. If both the taps operate simultaneously, how much time is needed to empty the tank?

    A)  18 minutes       

    B)  14 minutes

    C)  15 minutes       

    D)  30 minutes

    Correct Answer: A

    Solution :

    [a] Work done by \[{{1}^{st}}\] tap in one minute\[=\frac{1}{30}\] Work done by \[{{2}^{nd}}\] tap in one minute \[=\frac{1}{45}\] Both tap one minute work \[=\frac{1}{30}+\frac{1}{45}\] \[=\frac{45+30}{1350}\] \[=\frac{75}{1350}=18\]


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