The average age of 35 students in a group is 15 years. When the teacher's age is included, the average age of the group increases by 1.25 years. What is the teacher's age (in years)?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 60.
Total age of 35 students = 35 × 15 = 525 years
New average with teacher = 15 + 1.25 = 16.25 years
Total people now = 36
Total age including teacher = 36 × 16.25 = 585 years
Teacher's age = 585 − 525 = 60 years