The average age of 48 students of a class is 22 years. If the age of the teacher is also included, the average age of the whole group becomes 23 years. The age (in years) of the teacher is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 71.
Number of students = 48
Average age = 22 years
Total age of students = 48 × 22 = 1056
Including teacher, total people = 49
New average = 23
Total age including teacher = 49 × 23 = 1127
Teacher's age = 1127 − 1056 = 71