Question

The ratio of boys and girls in the school is 5 : 6. If 24 new boys are joined the school then the ratio of boys and girls becomes 9 : 10. Find the number of girls in the school?
1. 180
2. 200
3. 320
4. 360
5. 370

Answer 1

Correct Answer - Option 4 : 360

Given:

The ratio of boys and girls in the school is 5 : 6.

After joining 24 new boys, the the ratio of boys and girls becomes 9 : 10.

Calculation:

Let the number of boys in the school be 5x.

Then the number of girls in the school is 6x.

After joining 24 new boys, the number of boys  = 5x + 24

According to the question;

The new ratio of boys and girls = 9 : 10.

⇒ (5x + 24)/6x = 9/10

⇒ 50x + 240 = 54x

⇒  4x = 240

⇒ x = 60

Then, the number of girls = 60 × 6 = 360

∴ The number of girls in the school is 360.