The average age of 48 students of a class is 10 years. If the age of the teacher is also included, the average age of the whole group becomes 11 years. The age (in years) of the teacher is:

Correct option is C

Given:

Average age of 48 students = 10 years

Average age of 49 people (including teacher) = 11 years

Formula Used:

Total age = Average × Number of persons

Teacher’s age = Total age with teacher − Total age of students

Solution: ​

Total age of students = 48 $$\times$$​ 10 = 480

Total age with teacher = 49 $$\times$$​ 11 = 539

Teacher's age = 539 - 480 = 59 years