Question

The average age of a class is 19 years. While the average age of girls is 18 and that of boys is 21. If the number of girls in the class is 16, Find the number of Boys in the class?

Answer 1

average of the class.=19years
girls=18
boys=21

no of girls=16
sum of the age=16x18=188

sum of the age of the class.=19x(18+21)
=19x39=741

no of boys=741-188=553
=553÷21=21