SSC Sample Paper Mock Test-12 SSC CGL Tear-II Paper-1

  • question_answer
    Simplify \[\frac{3\sqrt{2}}{\sqrt{3}+\sqrt{6}}-\frac{4\sqrt{3}}{\sqrt{3}+\sqrt{6}}-\frac{\sqrt{6}}{\sqrt{2}+\sqrt{3}}\]

    A)  \[\sqrt{6}\]

    B)  \[\sqrt{3}\]

    C)  \[\sqrt{2}\]

    D)  0

    Correct Answer: D

    Solution :

    Firstly, we rationalise each term by its respective conjugate.
    1st term\[=\frac{3\sqrt{2}}{\sqrt{3}+\sqrt{6}}=\frac{3\sqrt{2}(\sqrt{6}-\sqrt{3})}{(\sqrt{6}+\sqrt{3})(\sqrt{6}-\sqrt{3})}=\frac{3\sqrt{2}(\sqrt{6}-\sqrt{3})}{6-3}\]
    \[=\sqrt{2}(\sqrt{6}-\sqrt{3})=\sqrt{12}-\sqrt{6}=2\sqrt{3}-\sqrt{6}\]
    2nd term \[=\frac{4\sqrt{3}}{\sqrt{6}+\sqrt{2}}=\frac{4\sqrt{3}(\sqrt{6}-\sqrt{2})}{(\sqrt{6}+\sqrt{2})(\sqrt{6}-\sqrt{2})}\]
    \[=\frac{4\sqrt{3}(\sqrt{6}-\sqrt{2})}{6-2}=\sqrt{6\times 3}-\sqrt{2\times 3}=3\sqrt{2}-\sqrt{6}\]3rd term \[=\frac{\sqrt{6}}{\sqrt{3}+\sqrt{2}}=\frac{\sqrt{6}(\sqrt{3}-\sqrt{2})}{(\sqrt{3}+\sqrt{2})(\sqrt{3}-\sqrt{2})}\]
    \[=\frac{\sqrt{6}(\sqrt{3}-\sqrt{2})}{3-2}=\sqrt{6\times 3}-\sqrt{6\times 3}=3\sqrt{2}-2\sqrt{3}\]\[\therefore \]The given expression
    \[=(2\sqrt{3}-\sqrt{6})-(3\sqrt{2}-\sqrt{6})+(3\sqrt{2}-2\sqrt{3})\]
    \[=2\sqrt{3}-\sqrt{6}-3\sqrt{2}+\sqrt{6}+3\sqrt{2}-2\sqrt{3}=0\]


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