Multiple choice

Find the average of the first 30 multiples of 9.

  1. 139.5

  2. 279

  3. 1395

  4. 270

  5. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Required average = 9(1 + 2 + 3 +.................. + 30)/30                                   = (9*30*31)/(30*2)                                   = 279/2                                   = 139.5