A list of five numbers is 5, 8, 8, 12, x. If the median of these numbers is 9, what is the mean of the list?

✓ Correct Answer: Option B

For the median to be 9, when the numbers are ordered, x must be 9. The ordered list is 5, 8, 8, 9, 12. The mean is (5 + 8 + 8 + 9 + 12) / 5 = 42 / 5 = 8.4.