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

Question : 1

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 : 2

The average age of 30 boys in a class is 15 years. One boy aged 20 years, left the class, but two new boys came in his place whose ages differ by 5 years. If the average age of all the boys now in the class still remains 15 years, the age of the younger newcomer is :

a) 15 years

b) 20 years

c) 8 years

d) 10 years

Question : 3

The average age of a husband and wife, who were married 4 years ago, was 25 years at the time of their marriage. The average age of the family consisting of husband, wife and a child, born during the interval is 20 years today. The age of the child is

a) 2 years

b) 1 year

c) 3 years

d) 2.5 years

Question : 4

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 : 5

The average age of Ram and his two children is 17 years and the average age of Ram’s wife and the same children is 16 years. If the age of Ram is 33 years, the age of his wife is (in years):

a) 32

b) 31

c) 30

d) 35

Question : 6

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