Railways Sample Paper RRBs Assistant Loco Pilot and Technician CBT STAGE-I Sample Paper-26

  • question_answer
    \[\{{{(49)}^{15}}-1\}\]is exactly divisible by

    A)  8                    

    B)  14

    C)  50       

    D)  51

    Correct Answer: A

    Solution :

    \[({{x}^{n}}-1)\]is divisible by \[(x+1)\],when n is even. \[[{{(49)}^{15}}-1]=\{{{({{7}^{2}})}^{15}}-1\}=\{{{(7)}^{30}}-1\},\] which is divisible by\[(7+1),\]i.e. 8.

You need to login to perform this action.
You will be redirected in 3 sec spinner