Question

the average age of boys is twice the number of girls in a class. if the ratio of boys and girls in the class of 36 is 5:1, what is the total ages (in yr) of the boys in class​

Answer 1

Firstly, lets consider the following data:

the ratio of boys and girls in the class of 36 is 5:1

This means that ,

5x+1x=36

6x=36

x=6

Therefore,

the number of boys in the class= 6

the number of girls in the class= 5*6= 30

Now, let us consider the following data:

the average age of boys is twice the number of girls in a class

This means that,

the average age of boys= (number of girls in a class) *2

Therefore,

the average age of boys= 30*2= 60

But,

average age of boys= (the sum of ages of all boys)/(the number of boys in the class)

This means that,

the sum of ages of all boys= (average age of boys)*(the number of boys in the class)

Therefore,

the sum of ages of all boys(in months)= 60*6= 360

the sum of ages of all boys(in years)= 360/12= 30

So here is your answer

the sum of ages of all boys(in years)= 30

the sum of ages of all boys