The average age of 26 students of a class is 43 years. If the age of the teacher is also included, the average age of the whole group becomes 44 years. The age (in years) of the teacher is:

Correct option is D

Given:

Average age of 26 students = 43 years

When teacher is included, group size = 27, new average = 44 years

Formula Used:

Total age = Average × Number of individuals

Solution:

Total age of 26 students = 26 × 43 = 1118

Total age of group of 27 = 27 × 44 = 1188

Age of teacher = 1188 - 1118 = 70 years