Carla's team won 3 of its 5 games. Elena's team won games at the same rate and won 12 games. How many games did Elena's team play?
We have: 3/5 = 12/?
Cross multiply:
3?= 512
⇒ ?= 5*12/3= 20
Elena's team played 20 games~
This is all about proportions. You can make this into fractions:
3/5 = 12/x
A good way to handle this, is to make one of those numbers the same. If you do (3/5) 4, you would get 12/20 (because 4 3 = 12 and 4 * 5 = 20)
So then you have this:
12/20 = 12/x
It's basically a fill in the blank from there. x= 20
Elena's team played 20 games