Question

The ratio of no. Of boys to the no. Of girls in a school of 450 student is 4:5 than sum new boys and girls are admite the no. Of boys increase 25 and the ratio of ratio of boys to girls change to 9:13 calculate the no. Of new girls admite

Answer 1

Solution :-

Total number of students = 1430 

Old ratio of number of boys to the number of girls = 7 : 6

Sum of the ratio = 7 + 6 = 13

Number of boys in the school = (7*1430)/13

⇒ 10010/13

Number of boys in the school = 770

Number of girls in the school = (6*1430)/13

⇒ 8580/13

Number of girls in the school = 660

Girls are admitted in the school = 26

Now, number of girls in the school after admission of 26 girls = 660 + 26

= 686

Let number of boys admitted in the school be x

Then, total number of boys = (770 + x)

New ratio = 8 : 7

(770 + x)/686 = 8/7

⇒ (770 + x)*7 = 686*8

⇒ 5390 + 7x = 5488

⇒ 7x = 5488 - 5390

⇒ 7x = 98

⇒ x = 98/7

⇒ x = 14

So, 14 boy should be admitted so that the ratio of number of boys to the number of girls changes to 8 : 7