Question
The average age of a class of 22 students is 21 years. The average increased by 1 when the teacher’s age also included. What is the age of the teacher?
A. 44
B. 48
C. 45
D. 43
Answer: A. 44
Solution:
Total age of students = 22 × 21
Total age of students + age of teacher =23 × 22
Age of the teacher
= 23 × 22 − 22 × 21
= 22 (23 − 21)
= 22 × 2
= 44
Hence, The age of the teacher is 44.