Question

The number of girls in a class is 4 more than the number of boys. On a day when only 8 boys were absent, the numbers of girls were double the number of boys. How many girls and boys are there in that class?

Answer 1

Let the number of boys in the class be x and the number of girls in the class be y.

The number of girls in the class is four more than the number of boys.

∴ y = x + 4 … (1)

Number of boys absent on a particular day = 8

∴ Number of boys present on that day = x − 8

According to the question:

⇒ 2(x − 8) = y

⇒ 2x − 16 = y

⇒ 2x − y = 16

Putting the value of y from equation (1):

2x − (x + 4) = 16

⇒ 2x − x − 4 = 16

⇒ x = 16 + 4

⇒ x = 20

From equation (1), we have:

y = 20 + 4 = 24

Thus, there are 20 boys and 24 girls in the class.