The average age of 24 boys and a class teacher of class is equal to 15 years. If class teacher left the class then the average becomes 14 years. Find the age of class teacher.

39 years

Avg. age of 24 Boys + 1 Teacher = 15 yrs.

Now, teacher left

Therefore, average of 24 boys = 14 yrs.

Age of teacher = (25 × 15) - (24 × 14) = 375 - 336 = 39 yrs.