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.

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 all the students of a class is 22 years. The average age of boys of the class is 24 years and that of the girls is 20 years. If the number of girls in the clss is 30, then the find the number of studnets in the class.

The average age of P , Q and R is 26 years . If the average age of P and R is 30 years . What is Q's age ?

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 ?

The average age of all the students of a class is 18 years. The average age of boys of the class is 20 years and that of the girls is 15 years. If the number of girls in the class is 20, then find the number of boys in the class. (a) 15 (b) 30 (c) 45 (d) 50

The average age of 30 girls is 13 yr. The average of first 18 girls is 15 yr. Find out the average age of remaining 12 girls.

The average age of A, B and C is 26 years. If the average age of A and C is 29 years, what is the age of B in years ?