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

Question : 1

Five years ago, the average age of P and Q was 25. The average age of P, Q and R today is 25. Age of R after 5 years will be

a) 20 years

b) 15 years

c) 35 years

d) 40 years

Question : 2

In a class, there are 40 boys and their average age is 16 years. One boy, aged 17 years, leaving the class and another joining, the average age becomes 15.875 years. The age of the new boy is :

a) 14.5 years

b) 12 years

c) 17 years

d) 15 years

Question : 3

The average age of 30 students is 9 years. If the age of their teacher is included, the average age becomes 10 years. The age of the teacher (in years) is

a) 31

b) 27

c) 40

d) 35

Question : 4

The average age of 8 persons is increased by 2 years, when one of them, whose age is 24 years is replaced by a new person. The age of the new person is :

a) 40 years

b) 42 years

c) 45 years

d) 38 years

Question : 5

Average age of 6 sons of a family is 8 years. Average age of sons together with their parents is 22 years. If the father is older than the mother by 8 years, the age of mother (in years) is :

a) 52

b) 44

c) 68

d) 60

Question : 6

If out of 10 selected students for an examination, 3 were of 20 years, age, 4 of 21 and 3 of 22 years, the average age of the group is

a) 21 years

b) 22 years

c) 20 years

d) 21.5 years