1.  A cricketer whose bowling average is 12.4 runs per wicket takes 5 wickets for 26 runs and thereby decreases his average by 0.4. The number of wickets taken by him till the last match was :
A. 64
B. 72
C. 80
D. 85

Answer: Option D

Explanation:

Let the number of wickets taken till the last match be x.

Then, 12.4x + 26 = 12
x+5

12.4x + 26 = 12x + 60

0.4x = 34

 x = 34 = 85
0.4