model 7 average on ages/weight Section-Wise Topic Notes With Detailed Explanation And Example Questions

Question : 1

Out of 10 teachers of a school, one teacher retires and at his place a new teacher of age 25 years joins. As a result of it, the average age of the teachers is reduced by 3 years. The age of the retired teacher is

a) 58 years

b) 60 years

c) 55 years

d) 56 years

Question : 2

The average age of a husband and a wife was 27 years when they married 4 years ago. The average age of the husband, the wife and a new-born child is 21 years now. The present age of the child is

a) 3 years

b) 4 years

c) 1 year

d) 2 years

Question : 3

In a school, the average age of students is 6 years, and the average age of 12 teachers is 40 years. If the average age of the combined group of all the teachers and students is 7 years, then the number of students is :

a) 400

b) 396

c) 416

d) 408

Question : 4

The average age of 14 girls and their teacher’s age is 15 years. If the teacher’s age is excluded, the average reduces by 1. What is the teacher’s age?

a) 32 years

b) 35 years

c) 29 years

d) 30 years

Question : 5

The average age of 20 boys in a class is 12 years. 5 new boys are admitted to the class whose average age is 7 years. The average age of the boys in the class becomes

a) 9.5 years

b) 8.2 years

c) 11 years

d) 12.5 years

Question : 6

In a class there are 30 boys and their average age is 17 years. On one boy aged 18 years leaving the class and another joining, the average age becomes 16.9 years. The age of new boy is

a) 11 years

b) 25 years

c) 15 years

d) 13 years