SSC SSC CHSL TIER-I Solved Paper Held on 09.01.2017

  • question_answer
    What is the value of two consecutive natural numbers, sum of whose squares is 145?

    A)  8, 9

    B)  6, 7

    C)  13, 14

    D)  9, 10

    Correct Answer: A

    Solution :

     Let the number be\[x\]and\[(x+1)\]. According to the question. \[{{x}^{2}}+{{(x+1)}^{2}}=145\] \[\Rightarrow {{x}^{2}}+{{x}^{2}}+2x+1=145\] \[\Rightarrow 2{{x}^{2}}+2x-144=0\] \[\Rightarrow {{x}^{2}}+x-72=0\] \[\Rightarrow {{x}^{2}}+9x-8x-72=0\] \[\Rightarrow x(x+9)-8(x+9)=0\] \[\Rightarrow (x-8)(x+9)=0\] \[\Rightarrow x=8\]because \[x\ne -9\] \[\therefore \]Number = 8 and 9 OR \[{{x}^{2}}+{{(x+1)}^{2}}=145\] \[=64+81={{8}^{2}}+{{9}^{2}}\] \[\Rightarrow x=8\]


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