Rafael is going to have a party. Three times as many girls as boys told Rafael they would come. If nine out of ten girls said they would come, and six boys said they could not come, how many people did Rafael INVITE to the party?
I'll start by assigning a few variables:
We can make a few equations:
And plug in what we know (
Use "Three times as many girls as boys told Rafael they would come" to make another equation:
So now we know:
Our last step, now that we know that