What is the average of all integers between 100 and 250 that are exactly divisible by 11?

Question

What is the average of all integers between 100 and 250 that are exactly divisible by 11?

1. A. 176 (Correct answer)
2. B. 186
3. C. 196
4. D. 146

Correct Answer

Option A — 176

Detailed Solution & Explanation

The correct answer is 176.

Key Points

• The multiples of 11 between 100 and 250 form an arithmetic series: 110, 121, …, 242.
• The mean of an evenly spaced series is just (first + last)/2 = (110 + 242)/2 = 352/2 = 176.
• For the average of an arithmetic progression you never need to add every term — the midpoint of the first and last terms is the mean.