Questions :
A batsman’s average score for a certain number of innings is 40. If he scores 150 runs in the next innings, his average becomes 45. How many innings did he play earlier?
Options :
- 21
- 22
- 23
- 24
correct answer : a)
Explanation :
Let the number of innings played earlier be n.
Total runs scored earlier = 40n
After scoring 150 runs in the next innings, the average becomes 45.
So,
40n + 150 = 45(n + 1)
⇒ 40n + 150 = 45n + 45
⇒ 150 − 45 = 45n − 40n
⇒ 105 = 5n
⇒ n = 105/5
⇒ n = 21
Therefore, the correct answer is option (a) 21. The values 22, 23, and 24 do not satisfy the given average condition and are therefore incorrect.