WAEC 2022 Mathematics · Question 21

The age (years) of some members in a singing group are: 12, 47, 49, 15, 43, 41, 13, 39, 43, 41 and 36. Find the mean

Options

A.33.35
B.35.54
C.34.45
D.36.44

Answer: C. 34.45

Explanation written with AI and checked against the answer key

Analyze the question: We need the mean (average) age of the 11 members.

Concept: Mean = (Sum of all values) ÷ (Number of values)

Solution:

Add the ages step by step:

12 + 47 = 59
59 + 49 = 108
108 + 15 = 123
123 + 43 = 166
166 + 41 = 207
207 + 13 = 220
220 + 39 = 259
259 + 43 = 302
302 + 41 = 343
343 + 36 = 379

Sum = 379, and there are 11 values.

Mean = 379 ÷ 11 = 34.4545... ≈ 34.45

Tip: When adding many numbers, count your data points first (here 11) so you divide by the right number. You can also group numbers that add to round figures, such as 12 + 47 + 41 = 100 to speed up your addition and reduce mistakes.

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