Question

The average age of 28 students of a class is 12 years. If their teacher’s age is included the average age increases by one year. Then the age of the teacher (in years) is
1. 41
2. 40
3. 39
4. 38

Answer 1

Correct Answer - Option 1 : 41

Given:

The average age of 28 students = 12 years

Formula Used:

Average = Sum of the observation/Total observation

Calculation

Total sum of age of 28 students = 12 × 28 = 336 years

⇒ After adding teacher new average = 13 years

⇒ New sum = 13 × 29 = 377 years

 Teacher's age is 377 - 336 = 41 years

∴ The age of the teacher (in years) is 41 years