The average age of 20 students is 12 years. If the teacher's age is included, the average increases by one year. What is the age of the teacher?
Q1. The average age of 20 students is 12 years. If the teacher's age is included, the average increases by one year. What is the age of the teacher?
Answer: 33 years
Explanation: New total age of 21 persons = 21 × 13 = 273. Old total age of 20 students = 20 × 12 = 240. Teacher's age = 273 − 240 = 33 years.