Batting average boost: A cricketer has some average after 9 innings. He scores 100 in the 10th innings and his average increases by 8. What is his average after the 10th innings?

Introduction / Context:
Average increase problems can be solved algebraically by expressing totals before and after the new data point. The single new score is the difference between the new total and the old total.

Given Data / Assumptions:

• Score in 10th innings = 100
• Average increases by 8 runs

Concept / Approach:
Let A be the new average after 10 innings. Then previous average was A - 8. Relate totals across 9 and 10 innings and equate the 10th score to the difference in totals.

Step-by-Step Solution:

Verification / Alternative check:
If A = 28, previous average = 20. Totals: 10 * 28 = 280; 9 * 20 = 180; difference = 100 for the 10th, as given.

Why Other Options Are Wrong:

• 20, 24, 26, 32: do not satisfy A + 72 = 100.

Common Pitfalls:
Setting the increase relative to the old total incorrectly, or assuming the increase applies to just one innings rather than the cumulative average.

Final Answer:
28