franklin school has 3 boys for every four girls in the fifth grade. there are 140 students in the fifth grade.

a.how many are boys?
b.how many are girls?

Add the ratio

3+4=7
So each part of the ratio is worth 7.
so then divide 140 by 7 = 20
Now we know there were 3 boys for every 4 girls
So the amount of boys in the school = 20 multiply by 3 = 60
The amount of girls in the school= 20 multiply by 4 = 80
So add 80 + 60= 140 so you got back what you started with