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

Question : 1

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

Question : 2

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 : 3

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 : 4

From a class of 42 boys, a boy aged 10 years goes away and in his place, a new boy is admitted. If on account of this change, the average age of the boys in that class increases by 2 months, the age of the newcomer is :

a) 17 years

b) 19 years

c) 12 years 2 months

d) 10 years 6 months

Question : 5

The average age of a family of 10 members is 20 years. If the age of the youngest member of the family is 10 years, then the average age of the members of the family just before the birth of the youngest member was approximately

a) 12.5 years

b) 27.14 years

c) 11$1/9$ years

d) 14.28 years

Question : 6

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 age differ by 5 years. If the average age of all the boys now in the class becomes 15 years, the age of the younger newcomer is :

a) 15 years

b) 20 years

c) 8 years

d) 10 years