Wednesday 15 August 2018

Question of the day


There is a 7-digit telephone number with all different digits. If the digit at extreme right and extreme left are 5 and 6 respectively, find how many such telephone numbers are possible? 

A) 120

  B) 100000

C) 6720

  D) 30240


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1 comment:

  1. Bhaskar Reddy15 August 2018 at 21:17

    Answer - C) 6720


    Description :
    There is a 7-digit telephone number but extreme right and extreme left positions are fixed

    ie.., 6 x x x x x 5

    So the required number of ways = 8 x 7 x 6 x 5 x 4 = 6720

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