Banking Sample Paper SBI Clerk Grade (Main) Sample Test Paper-6

  • question_answer
    The difference between two numbers is 18 and their H.C.F. and L.C.M. are 6 and 168 respectively. What is the sum of squares of the two numbers?

    A)  2280

    B)  2260

    C)  2420

    D)  2340

    E)  2380

    Correct Answer: D

    Solution :

     Let the numbers be 6x and 6y where x and y are co-primes. According to the question, \[6x-6y=18\] \[\Rightarrow 6\left( x-y \right)=18\] \[\Rightarrow x-y=3~\]                            ..... (i) Product of numbers = HCF \[\times ~\]LCM \[\Rightarrow \,6x\times 6y=6\times 168\] \[\Rightarrow xy=\frac{168}{6}=28\]                   ??. (ii) On squaring equation (i), \[{{(x-y)}^{2}}={{3}^{2}}\] \[\Rightarrow \,\,{{x}^{2}}+{{y}^{2}}-2xy=9\] \[\Rightarrow \,\,{{x}^{2}}+{{y}^{2}}-2\times 28=9\] \[\Rightarrow \,\,{{x}^{2}}+{{y}^{2}}=9+56=65\] \[\therefore \,\,36{{x}^{2}}+36{{y}^{2}}=36\times 65=2340\]


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