NECO 2001 Mathematics · Question 1

If the mean of 3, 5, 8, k, 14 and 17 is 11, what is the value of k

Options

A.58
B.38
C.19
D.11
E.967

Answer: C. 19

Explanation written with AI and checked against the answer key

Analyze the question: We have six numbers: 3, 5, 8, k, 14 and 17. Their mean is 11, and we need to find k. Concept: Mean = (sum of all values) ÷ (number of values) Solution: Number of values = 6, so the total must be: 6 × 11 = 66 Add the known numbers: 3 + 5 + 8 + 14 + 17 = 47 So: 47 + k = 66 k = 66 − 47 k = 19 Check: (3 + 5 + 8 + 19 + 14 + 17) ÷ 6 = 66 ÷ 6 = 11 ✓ Tip: For "find the missing value given the mean" questions, multiply the mean by the number of items to get the total, then subtract the known values. Don't forget to count the unknown k as one of the items. Here that makes 6 numbers, not 5.

AI can make mistakes. Report anything that looks wrong.