The average age of 5 boys is 20. If the average age of 4 of them is 18, find the age of the fifth boy.

The average age of r boys in a class is a years. If the average age of s of them is b years, them what is the average age of the remaining boys ?

In a class, the number of boys and girls are distinct. The average age of all the student in the class equals the average of the average age of the boys and the average age of the girls. The sum of the average age of the boys and the average age of the girls is 10 years. Find the average age (in years) of the boys of the class

The average age of three boys is 15yr . If the ratio of their ages is 3:5:7 , what is the age of the oldest boy ?

The average age of 80 girls was 20 years, the average age of 20 of them was 22 years and that of another 20 was 24 years. Find the average age of the remaining girls.

In a group of 150 people , (2)/(5) are men, (1)/(3) are women and the rest are children . The average age of the women is (4)/(5) of the average age of the men . The average age of the children is (1)/(5) of the average age of the men . If the average age of the men is 50 years, then the average age of all the people in the group is :

There are 30 boys and 60 girls in a class . If the average age of boys is 12yr and average age of girls is 10yr , then find out the average age of the whole class .

Average age of a group of 30 boys is 16 years. A boy of age 19 leaves the group and a new boy joins the group. If the new average age of the group is 15.8 years, find the age of the new boy.

The average age of three boys is 16 years. If their ages are in the ratio 4:5:7, then the age of youngest boy is

In a colony, the average age of the boys is 14 years and the average age of the girls is 17 years. If the average age of the children in the colony is 15 years, find the ratio of number of boys to that of girls.