Multiple choice general knowledge math & puzzles

A cricketer whose average is 12.4 takes 5 wickets for 26 runs andb thereby decreasing his average by 0.4. The number of wickets taken by him before last match is:

  1. 82

  2. 84

  3. 85

  4. 83

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

Let w be wickets before. Then (12.4w + 26)/(w + 5) = 12.0, giving 12.4w + 26 = 12w + 60, so 0.4w = 34 and w = 85. The decrease by 0.4 in average means 85 wickets were taken before the last match.