A batsman scores 87 runs in his 17th innings, and his batting average increases by 3 runs.\nFind his average after the 17th innings.

Introduction / Context:
Batting average is total runs divided by number of innings. An increase after a specific innings allows us to set up a linear equation between totals before and after that innings to find the new average directly.

Given Data / Assumptions:

• Score in 17th innings = 87.
• Average increases by 3 runs after the 17th innings.

Concept / Approach:
Let x be the previous average after 16 innings. Then total after 16 innings is 16x. After scoring 87, the new total is 16x + 87, and the new average is x + 3 over 17 innings.

Step-by-Step Solution:

Verification / Alternative check:
If average after 16 innings was 36, total was 576. Adding 87 makes 663; 663/17 = 39 exactly.

Why Other Options Are Wrong:
40, 50, 55 do not satisfy the linear relation formed by the given increase and the specific score of 87.

Final Answer:
39