SSC Sample Paper SSC CGL - Sample Paper-13

  • question_answer
    P and Q can do a job in 2 days; Q and R can do it in 4 days; and P and R in 12/5 days. What is the number of days required for P alone to do the job?

    A) 5/ 2                              

    B) 3

    C) 14/5                             

    D) 6

    Correct Answer: B

    Solution :

    One day work of P and Q \[=\frac{1}{2}\] One day work of Q and R \[=\frac{1}{4}\] One day work of P and R \[=\frac{5}{12}\] On adding Eqs. (i), (ii) and (in), we get             \[2(P+Q+R)=\frac{1}{2}+\frac{1}{4}+\frac{1}{5}\] \[\Rightarrow \]   \[2(P+Q+R)=\frac{14}{12}\] \[\Rightarrow \]   \[P+Q+R=\frac{7}{12}\] On subtracting Eq. (ii) from Eq. (iv), we get             \[P=\frac{7}{12}-\frac{1}{4}\] \[\Rightarrow \]   \[P=\frac{1}{3}\] Hence, P can do alone in 3 days.

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