Question

The ratio of number of boys and girls in a school of 770 students in 7 ratio 15 how many more boys should be admitted to make the ratio of 1 ratio 1

Answer 1

Total number of students in school = 770

Ratio of boys and girls in school is = 7: 15

So, fraction of boys = 7/22

fraction of girls = 15/22

Number of boys = 7/22 * 770 = 245

Number of girls = 15/22 * 770 = 525

Now, to make the ratio 1 : 1, the number of girls should be equal to number of boys.

Currently number of girls is 525 and boys is 245

So, number of boys we need to equal number of girls will be = 525 - 245 = 280

Therefore, we need 280 more boys to have ratio 1:1

Answer 2

Hello Dear.

Let the Original number of boys and girls in the school be 7x and 15x respectively.

Number of boys +Number of girls = 770
⇒ 7x + 15x = 770
⇒ 22x = 770
⇒ x = 35

∴ Number of boys = 7x
 = 7 × 35
 = 245 boys.

Number of girls = 15x 
= 15 × 35
= 525 girls.


Now, Let the number of boys admitted be y.
∴ New number of boys = 245 + y

According to the Question,
New Number of boys/Number of girls = 1/1
∴ (245 + y)/525 = 1/1
⇒ 245 + y = 525
⇒ y = 525 - 245
⇒ y = 280.


Hence, the number of boys admitted to make the ratio of the number of boys to number of girls 1 : 1 is 280.


Hope it helps.