Eli is making a party mix that contains pretzels and chex. For each cup of pretzels, he uses 3 cups of chex. How many cups of pretzels and how many cups of chex does he need to make 12 cups of party mix?
So for every one cup of pretzels (1p) You have three cups of chex (3c)
The ratio between pretzels and chex is 1p:3c
Thus, changes in 1 is proportional with changes in 3.
You need a total of 12 cups of party mix. The sum of the ratio 1 cup of pretzels and 3 cups of chex is 4.
So you would need 3 cups of pretzels and 9 cups of chex for the ratio to equal a sum of 12.