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?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 21.
Let the number of innings played earlier = n
Total runs scored earlier = 40n
So, 40n + 150 = 45(n + 1)
⇒ 40n + 150 = 45n + 45
⇒ 5n = 105
⇒ n = 105/5 = 21