The average age of 24 students is 15 years. If the teacher’s age is included, the average rises by 1 year. Later, another teacher joins, and the average rises by 1 more year. What is the age of the second teacher?
Show answer & explanation
Correct answer: A
Explanation
Given:
Average age of 24 students = 15 years
Average with the first teacher = 16 years
Average with the second teacher = 17 years
Total age of students = 24 × 15 = 360
With the first teacher
Total number of people = 25
Total age = 25 × 16 = 400
Age of the first teacher = 400 − 360 = 40
With the second teacher
Total number of people = 26
Total age = 26 × 17 = 442
Age of the second teacher = 442 − 400 = 42 years