Question

The average age of boys in the class is twice the number of girls in the class. The ratio of boys and girls in the class of 50 is 4:1. Find The total of the ages of the boys in the class

Answer 1

Number of students in the class = 50

Ratio of Boys : Girls = 4 : 1

Define x :

Let x be the constant ratio

Ratio of Boys : Girls = 4x : 1x

Sum of their age is 50

4x + 1x = 50

5x = 50

x = 10

Find the number of boys and girls:

girls = x = 10

boys = 4x = 4(10) = 40

Find the average of the boys' age:

average = 2 x number of girls = 2(10) = 20

Find the sum of the boy's age:

Average of the age of the 40 boys = 20

sum of the age of the 40 boys = 20 x 40 = 800 years

Answer: The total of the age of the boys is 800 years old

Answer 2

Number of students in the class = 50

Ratio of Boys : Girls = 4 : 1

Let p :

Let p be the ratio

Ratio of Boys : Girls = 4p : 1p

Sum of their age is 50

4p + 1p = 50

5p = 50

p = $\bf\huge\frac{50}{5}$

p = 10

The number of boys and girls:

Girls => p = 10

Boys = 4p

=> 4 × 10 = 40

The average of the boys' age:

Average = 2 x number of girls

=> 2 × 10 = 20

The sum of the boy's age:

Average of the age of the 40 boys

= 20

Sum of the age of the 40 boys

= 20 x 40

= 800 years