Cricket batting average adjustment: A batsman has a certain average for 14 innings. In the 15th innings he scores 72 runs, and his average increases by 2 runs. What is his new average after 15 innings?

Difficulty: Medium

Correct Answer: 44

Explanation:


Introduction / Context:
This problem tests average (arithmetic mean) update when one additional data point is appended and the average changes by a known amount.


Given Data / Assumptions:

  • Average after 14 innings = x
  • 15th score = 72
  • New average increases by 2, so new average = x + 2


Concept / Approach:
For n items with average x, total is n * x. After adding a new score s, new average is (n * x + s) / (n + 1). Set this equal to x + 2 and solve for x, then compute the new average.


Step-by-Step Solution:
(14 * x + 72) / 15 = x + 214x + 72 = 15x + 3072 - 30 = 15x - 14xx = 42New average = x + 2 = 44


Verification / Alternative check:
Total after 14 innings = 14 * 42 = 588. Add 72 gives 660. 660 / 15 = 44. Correct.


Why Other Options Are Wrong:
46, 42, 48, 40 are inconsistent with the equation and totals computed above.


Common Pitfalls:
Confusing the previous average with the new one or dividing by 14 instead of 15 after the last innings.


Final Answer:
44

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