The average age of 28 students of a class is 40 years. If the age of the teacher is also included, the average age of the whole group becomes 41 years. The age (in years) of the teacher is:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 69.
Average age of 28 students = 40, including teacher average = 41
Total age of 28 students = 28 × 40 = 1120
Total with teacher = 29 × 41 = 1189
Teacher’s age = 1189 - 1120 = 69