Question

Q1.in a school the ratio of the number of the boys to the number of girls 4:5 when 100 girls leave the school the ratio becomes 6:7 find the number of boys in the sschook.

Answer 1

Explanation:

Answer:

There are 1,200 boys in school. Step-by-step explanation:

Let,

The number of the boys in a school = 4x

The number of the girls in a school = 5x

When 100 girls leave the school

The number of the girls in a school = 5x - 100

Also,

The ratio becomes 6 : 7

So,

$\sf{\dfrac{4x}{5x \: - \: 100} \: = \: \dfrac{6}{7}} </p><p>$

⇒ 7 (4x) = 6 (5x -100)

⇒ 28x = 30x - 600

⇒ 28x - 30x = - 600

⇒ - 2x = - 600

⇒ 2x = 600

⇒ x = 600 / 2

⇒ x = 300

___________________

The number of the boys in a school = 4x

⇒ 4 (300)

⇒ 1200

Therefore, there are 1,200 boys in school.