NECO 2008 Mathematics · Question 26

The ages of Abu, Segun, Kofi and Funmi are 17 years, (2x -13) years, 14 years and 16 years respectively. What…

Question

The ages of Abu, Segun, Kofi and Funmi are 17 years, (2x -13) years, 14 years and 16 years respectively. What is the value of x if their mean ages is 17.5 years?

A.18
B.23
C.25
D.36
E.70

Answer: A. 18

Explanation written with AI and checked against the answer key

Analyze the question: Four people have ages 17, (2x − 13), 14 and 16. Their mean age is 17.5. We need x. Concept: Mean = (sum of all values) ÷ (number of values) Solution: Sum of ages = 17 + (2x − 13) + 14 + 16 = 2x + 34 Mean = (2x + 34) / 4 = 17.5 Multiply both sides by 4: 2x + 34 = 70 2x = 36 x = 18 Check: Segun's age = 2(18) − 13 = 23. Sum = 17 + 23 + 14 + 16 = 70, and 70 ÷ 4 = 17.5 ✓ The value of x is 18, which is option A. Tip: In "mean" questions, always multiply the mean by the number of items to get the total (17.5 × 4 = 70), then set up your equation. Also, be careful not to confuse 70 (the total age, option E) with x, the answer.

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