Railways Sample Paper RRB (Group D) Sample Test Paper-12

  • question_answer
    If \[{{3}^{2x-\,y=}}{{3}^{\times +y=}}\,\,\sqrt{27}\], then the value of \[{{3}^{x-y}}\] will be:

    A)  \[\frac{1}{\sqrt{3}}\]                

    B)  \[\frac{1}{\sqrt{27}}\]

    C)  \[\sqrt{3}\]                   

    D)  3

    Correct Answer: C

    Solution :

    [c] \[{{3}^{2x-\,y}}={{3}^{x+y}}=\sqrt{27}={{3}^{\frac{3}{2}}}\] \[\Rightarrow \,\,\,2x-\,y=\frac{3}{2}\,\,x+y=\frac{3}{2}\] \[4x-\,2y=3\] \[2x+2y=3\] Solving equation (i) and (ii) \[x=1\]  \[y=\frac{1}{2}\] \[\Rightarrow \,\,\,{{3}^{1-\,\frac{1}{2}}}={{3}^{\frac{1}{2}}}=\sqrt{3}\]


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