Banking Quantitative Aptitude Sample Paper Quantitative Aptitude Sample Paper-35

  • question_answer
    Find the value of \[m-n,\]if \[\frac{{{9}^{n}}\times {{3}^{2}}\times {{\left( {{3}^{-\frac{n}{2}}} \right)}^{-2}}-{{(27)}^{n}}}{{{3}^{3m}}\times {{2}^{3}}}=\frac{1}{27}\]

    A) \[1\]     

    B) \[-\,\,2\]

    C) \[-\,\,1\]                        

    D) \[2\]

    Correct Answer: A

    Solution :

    \[\frac{{{9}^{n}}\times {{3}^{2}}\times {{({{3}^{-n/2}})}^{-2}}-{{(27)}^{n}}}{{{3}^{3m}}\times {{2}^{3}}}=\frac{1}{27}\]
    \[\Rightarrow \]\[\frac{{{3}^{2n}}\times {{3}^{2}}\times {{3}^{n}}\times {{3}^{3n}}}{{{3}^{3m}}\times {{2}^{3}}}=\frac{1}{27}\]\[\Rightarrow \]\[\frac{{{3}^{3n+2}}-{{3}^{3n}}}{{{3}^{3m}}\times 8}=\frac{1}{27}\]
    \[\Rightarrow \]   \[\frac{{{3}^{3n}}\times 8}{{{3}^{3m}}\times 8}=\frac{1}{{{(3)}^{3}}}\]\[\Rightarrow \]\[{{\{{{(3)}^{3}}\}}^{n-\,\,m}}={{3}^{-\,\,3}}\]
    \[\Rightarrow \]   \[n-m=-1\]or \[m-n=1\]


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