Find the 13th result. If

The average of 25 result is 18. The average of first 12 of them is 14 and that of the last 12 is 17. Find the 13th result.

  1. 71
  2. 75
  3. 72
  4. 78
Monis Rasool Professor Asked on 9th June 2015 in Maths.
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  • 1 Answer(s)

    Answer: (4) 78
    Explanation:-
    The average of 25 results = 18
    The sum of 25 results = 18 x 25 = 450

    The average of first 12 results = 14
    the sum of first 12 results = 14 x 12 = 168

    The average of last 12 results = 17
    the sum of last 12 results = 17 x 12 = 204

    Thus, the 13th number = 450 – (168 + 204)
    = 450 – 372
    = 78

    Hence, the 13th number is 78.

    Anurag Mishra Professor Answered on 9th June 2015.
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