In a school with 600 students, the average age of the boys is 12 years and that of the girls is 11 years. If the average age of the school is 11 years 9 months, then the number of girls in the school is: (a) 150     (b) 250    (c) 350    (d) 450

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.

The average age of 12 boys is 15 years and the average age of 18 girls is 12 years .What is the conbined average age of the boys and girls ,taken together ?

Average age of A and B is 30 years, that of B and C is 32 years and the average age of C and A is 34 years. The age of C is

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 student is :

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 students of a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years. The ratio of the number of boys to the number of girls in the class is (a) 1 : 2 (b) 2 : 3 (c) 3 : 4 (d) 3 : 5

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 ?