SSC Sample Paper SSC CGL - Sample Paper-10

  • question_answer
    A well 20 m in diameter is dug 14 m deep and the earth taken out is spread all around it to a width of 5 m to form an embankment. The height of the embankment is

    A)  10 m               

    B)  11 m

    C)  11.2 m

    D)  11.5 m

    Correct Answer: C

    Solution :

    Radius of the base of well \[=\frac{20}{2}=10\,m\] Volume of the earth taken out \[=\pi {{r}^{2}}h\]             \[=\frac{22}{7}\times {{10}^{2}}\times 14\,{{m}^{3}}\] Let the height of embankment be x metres. Then, Volume \[=\pi ({{R}^{2}}-{{r}^{2}})\times x,\] where R             \[=15\,m,\] \[r=10\,m\] \[=\frac{22}{7}\times ({{15}^{2}}-{{10}^{2}})\times x\]             \[=\frac{22}{7}\times 25\times 5\times x\] Clearly,             \[\frac{22}{7}\times 25\times 5\times x\frac{22}{7}\times {{10}^{2}}\times 14\] \[\Rightarrow \]   \[x=\frac{100\times 14}{25\times 5}\]              \[=11.2\,m\]    

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