The average age of 40 students in a class is 12 years. The average age of group of 5 of students is 10 years and that of another group of 5 of them is 14 years. The average age of the remaining students is:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 12 years .
Total number of students = 40
Average age = 12 years
Total age = 40 × 12 = 480 years
First group of 5 students , Average = 10 → Total age = 5 × 10 = 50
Second group of 5 students, Average = 14 → Total age = 5 × 14 = 70
Remaining students = 40 − 5 − 5 = 30
Total age of remaining students = 480 − 50 − 70 = 360
Average age of remaining students = 360 ÷ 30 = 12 years