8th Class Mathematics Exponents and Power Question Bank Exponents and Powers

  • question_answer
    Simplify: \[\frac{{{\left[ \frac{2}{3} \right]}^{3}}\times {{\left[ \frac{2}{3} \right]}^{-2}}\times {{\left[ {{\left( \frac{1}{2} \right)}^{2}} \right]}^{-2}}\times \frac{1}{24}}{{{\left( \frac{2}{3} \right)}^{-5}}\times {{\left( \frac{3}{2} \right)}^{-12}}}\]

    A)  \[{{\left( \frac{2}{3} \right)}^{-4}}\]                      

    B)  \[\frac{32}{3}\]         

    C)  \[\frac{243}{16}\]     

    D)         \[\frac{243}{32}\]

    Correct Answer: D

    Solution :

    We have, \[\frac{{{\left[ \frac{2}{3} \right]}^{3}}\times {{\left[ \frac{2}{3} \right]}^{-2}}\times {{\left[ {{\left( \frac{1}{2} \right)}^{2}} \right]}^{-2}}\times \frac{1}{24}}{{{\left( \frac{2}{3} \right)}^{-5}}\times {{\left( \frac{3}{2} \right)}^{-12}}}\] \[=\frac{{{\left( \frac{2}{3} \right)}^{3-2}}\times {{\left( \frac{1}{2} \right)}^{-4}}\times \frac{1}{24}}{{{\left( \frac{2}{3} \right)}^{12-5}}}=\frac{\frac{2}{3}\times {{2}^{4}}\times \frac{1}{24}}{{{\left( \frac{2}{3} \right)}^{7}}}\] \[=\frac{{{2}^{5}}}{3}\times \frac{1}{{{2}^{3}}\times 3}\times \frac{{{3}^{7}}}{{{2}^{7}}}=\frac{{{3}^{7-2}}}{{{2}^{7+3-5}}}=\frac{{{3}^{5}}}{{{2}^{5}}}=\frac{243}{32}\]


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