SSC Sample Paper Mock Test-1 SSC CGL Tear-II Paper-1

  • question_answer
    What is the value of \[\frac{1}{\sqrt{9}-\sqrt{8}}-\frac{1}{\sqrt{8}-\sqrt{7}}+\frac{1}{\sqrt{7}-\sqrt{6}}-\frac{1}{\sqrt{6}-\sqrt{5}}+\frac{1}{\sqrt{5}-\sqrt{4}}\]is

    A)  \[0\]                            

    B)  \[1\]   

    C)  \[5\]    

    D)  \[\frac{1}{3}\]

    Correct Answer: C

    Solution :

    \[\frac{1}{\sqrt{9}-\sqrt{8}}-\frac{1}{\sqrt{8}-\sqrt{7}}+\frac{1}{\sqrt{7}-\sqrt{6}}-\frac{1}{\sqrt{6}-\sqrt{5}}+\frac{1}{\sqrt{5}-\sqrt{4}}\] On rationalization, \[(\sqrt{9}+\sqrt{8})-(\sqrt{8}+\sqrt{7})+(\sqrt{7}+\sqrt{6})-(\sqrt{6}+\sqrt{5})+\sqrt{5}+\sqrt{4}\]\[=\sqrt{9}+\sqrt{8}-\sqrt{8}-\sqrt{7}+\sqrt{7}+\sqrt{6}-\sqrt{6}-\sqrt{5}+\sqrt{5}+\sqrt{4}\]\[=\sqrt{9}+\sqrt{4}=3+2=5\]


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