SSC Sample Paper SSC CGL - Sample Paper-20

  • question_answer
    If \[\frac{\frac{1}{\sqrt{9}}-\frac{1}{\sqrt{11}}}{\frac{1}{\frac{1}{\sqrt{9}}+\frac{1}{\sqrt{11}}}}\times \frac{10+\sqrt{99}}{x}=\frac{1}{2},\] then the value of x is

    A) 2                     

    B) 3

    C) 4                                 

    D) None of these

    Correct Answer: A

    Solution :

    \[\frac{\frac{1}{\sqrt{9}}-\frac{1}{\sqrt{11}}}{\frac{1}{\sqrt{9}}+\frac{1}{\sqrt{11}}}\times \frac{10+\sqrt{99}}{x}=\frac{1}{2}\] \[\Rightarrow \]   \[\frac{11\sqrt{9}-9\sqrt{11}}{11\sqrt{9}+9\sqrt{11}}\times \frac{10+\sqrt{99}}{x}=\frac{1}{2}\] \[\Rightarrow \]   \[\frac{{{(11\sqrt{9}-\sqrt{11})}^{2}}}{1089+891}\times 10+\sqrt{99}\times 2=x\] \[\Rightarrow \]   \[x=\frac{2(1089+891)-198\sqrt{99})(10+\sqrt{99)}}{198}\] \[\Rightarrow \]   \[x=(10-\sqrt{99})(10+\sqrt{99})\]             \[=2(100-99)=2\]          


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