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

Question : 1

The average age of 5 boys is 12 years. The average age of 3 others is 16 years. The average age of all the 8 boys is :

a) 14 years

b) 13$1/2$ years

c) 13 years

d) 12$1/2$ years

Question : 2

Five years ago, the average age of P, Q and R was 25 years and seven years ago, the average age of Q and R was 20 years. The present age of P is

a) 29 years

b) 36 years

c) 21 years

d) 24 years

Question : 3

The average age of 40 students of a class is 15 years. When 10 new students are admitted, the average is increased by 0.2 year. The average age of the new students is :

a) 16 years

b) 15.2 years

c) 16.4 years

d) 16.2 years

Question : 4

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 : 5

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 : 6

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