Question

the ratio of the number of boys to the number of girls in a school with 840 student was 7:5 in the new session, the number of boys increased by 20 and the ratio of boys to girls change to 6:5 calculate the number of new girls​

Answer 1

Step-by-step explanation:

total number of students = 840

number of boys =7x

number of girls = 5x

so, 7x+20/5x+20 = 6/5

(7x+20)5 = (5x+20)6

35x+100 = 30x+120

35x-30x = 120 - 100

5x = 20

x = 20/5 = 4

So number of girls = 5*4+20

= 40

I think this is the answer