SSC Sample Paper SSC CGL - Sample Paper-7

  • question_answer
    A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 2 days B had to leave and A alone completed the remaining work. The whole work was completed in

    A)  10 days

    B)  8 days

    C)  12 days                       

    D)  15 days

    Correct Answer: A

    Solution :

    One day's work of \[A=\frac{1}{15}\] One day's work of \[B=\frac{1}{10}\] Two day's work of A and B together             \[=2\left( \frac{1}{15}+\frac{1}{10} \right)=\frac{1}{3}\] Remaining work \[=1-\frac{1}{3}=\frac{2}{3}\]             \[\overset{Work}{\mathop{_{\frac{2}{3}}^{1}\mathop{\downarrow }_{{}}^{{}}}}\,\]                \[\overset{Days}{\mathop{_{x}^{15}\mathop{\downarrow }_{{}}^{{}}}}\,\] \[\therefore \]      \[1:\frac{2}{3}::15:3\] \[\Rightarrow \]   \[x=\frac{2\times 15}{13}=10\] \[\therefore \] The whole work is completed in 12 days.                    


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