WAEC Mathematics 2017 Objective — Question 28
Question 28 of 50 from the West African Examinations Council (WAEC) Mathematics 2017 Objective paper, with the correct answer and a full explanation.
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The average age of a group of 25 girls is 10 years. If one girl, aged 12 years and 4 months joins the group, find, correct to one decimal place, the new average age of the group.
- A. A. 10.1 yearsCorrect
- B. B. 9.3 years
- C. C. 8.7 years
- D. D. 8.3 years
Explanation
Sum of ages = 25x10=250 years. New girl's age = 12 4/12 = 12 1/3 years. New sum = 250+12 1/3 = 250+37/3. New average = (250+37/3)/26 = (250+12.33)/26 ≈ 10.1 years.
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