Question

At present the average age of 20 students of class ten is 15.5 years. The present age of the class teacher is 47 years. What will be the average age of the students and the class teacher after 5 years?

• A. 21.8
• B. 21.5
• C. 22
• D. 22.8

Answer 1

Answer:

C. 22

Sum of the present ages of 20 students = 15.5 × 20 = 310 years Sum of the present ages of 20 students and the teacher = 310 + 47 = 357 years Sum of the ages of 20 students and the teacher after 5 years = 357 + 21 × 5 = 462 years The average age of 20 students and the teacher = 462/21 = 22 years