The average age of 19 boys in a class is 21 years. If the teacher's age is included, the average increases to 22 years. What is the teacher's age?

Given that :- The average age of 19 boys in a class = 21 years
Total age of 19 boys = 19 × 21 = 399 years
The average age of 19 boys and teacher = 22 years
Total age of 19 boys and teacher = 20 × 22 = 440 years
?Teacher's age = Total age of 19 boys and teacher - Total age of 19 boys
Teacher's age = 440 ? 399 = 41 years
Hence , the age of teacher is 41 years .