Manipal Engineering Manipal Engineering Solved Paper-2015

  • question_answer
    The number of positive integral solutions of \[\frac{{{a}_{1}}+{{a}_{2}}+...+{{a}_{n}}}{n}\]is

    A) 2                                             

    B)  3

    C) 4                                             

    D) 5

    Correct Answer: D

    Solution :

                    We have,\[{{x}^{2}}+9<{{(x+3)}^{2}}<8x+25\] \[\Rightarrow \]\[{{x}^{2}}+9<{{x}^{2}}+6x+9<8x+25\] \[\Rightarrow \]\[{{x}^{2}}+9<{{x}^{2}}+6x+9\] and\[{{x}^{2}}+6x+9<8x+25\] \[\Rightarrow \]\[6x>0\]and\[{{x}^{2}}-2x-16<0\] \[\Rightarrow \]\[x>0\]and\[1-\sqrt{17}<x<1+\sqrt{17}\] \[\Rightarrow \]\[0<x<1+\sqrt{17}\] \[\therefore \]x = 1, 2, 3, 4, 5


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