Answer:
128
Explanation:
There are a couple of ways to go at this. One is to use a proportion:
(10 servings)/(1.25 cups) = (x servings)/(16 cups)
160/1.25 = x = 128 . . . . . . . multiply by 16 and simplify
1 gallon of milk will make 128 servings.
__
Another way to go at this is to figure out how much milk is used in one serving. It is ...
1.25 cups/(10 servings) = 0.125 cups/serving = 1/8 cup/serving
Now, you can work with several different conversion factors:
1 cup = 8 oz
1 gal = 128 oz
1 gal = 16 cups
Obviously 1/8 cup is 1 oz. Since there are 128 oz in a gallon, the gallon will make 128 servings.
__
Or, you can divide 16 cups by (1/8 cup/serving) to find the number of servings:
(16 cups/gal)/(1/8 cup/serving) = 16·8 servings/gal = 128 servings/gal