The average (arithmetic mean) of 7 numbers is 15. If a new number, 23, is added to the set, what is the new average of the 8 numbers?

✓ Correct Answer: Option A

The sum of the original 7 numbers is 7 * 15 = 105. When 23 is added, the new sum is 105 + 23 = 128. The new average is 128 / 8 = 16.