Question 7
Measures of Central Tendency7 pupils of average age 12 years leave a class of 25 pupils of average age 14 years. If 6 new pupils of average age 11 years join the class, what is the average age of the pupils now in the class?
- A.13 years
- B.12 years 7½ months
- C.13 years 5 months
- D.13 years 10 months
- E.11 years.
Show the answer and explanation
Answer: D (13 years 10 months)
Explanation
Total age = 25 × 14 − 7 × 12 + 6 × 11 = 350 − 84 + 66 = 332 years for 24 pupils. 332 ÷ 24 ≈ 13.83 years = 13 years 10 months.