Question

A punch recipe says to mix 4 cups pineapple juice 8 cups orange juice and 12 cups seltzer in order to make 18 servers of punch.How many servers can be made from 108 cups of punch?

Answer 1

81 servings. I found this by making a ratio:
24 c            108 c
-------     =    -------
18 ser            x
I then cross multiplied to get the equation: 24x=1,944. I solved this equation to find x, the number of servings in 108 cups, which was 81. 

I remember doing this back in elementary school. I had a hard time with it too!