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Discussion

  1. The average of 5 consecutive number is n , if the next two number are also include, the average of 7 number will ?
    1. Increase by 2
    2. increase by 1
    3. Remains the same
    4. Increase by 1.4
  1. Correct Option: B

    Sum of 5 consecutive integers
    x + ( x +1 ) + ( x +2 ) + ( x + 3 ) + ( x +4 ) = 5n
    ⇒ 5x + 10 = 5n
    ⇒ x = ( n – 2 ) ......(i)

    Average of 7 consecutive integers
    = [( 5x + 10 ) + ( x + 5 ) + ( x + 6 )] / 7
    = 7x + 21 / 7
    = x + 3 .....(ii)

    from eq. (i) and (ii)
    New average = x + 3 = ( n – 2 + 3 ) = n + 1
    So , the new average increases by 1 .

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