Question

the ratio of boys to girls in the classroom is 12:25 if there are 120boys how many girls are there​

Answer 1

Call x is the number of girls in the classroom.
12/120 = 25/x
x = 120*25/12
x=250
Answer 250 girsl

Answer 2

Ask yourself what do I have to multiply by 12 to get an answer of 120 ( you can just do 120/12, which is 10) then, you multiply the other side by ten as well