6
That is 20 servings
A half gallon has 64 fluid ounces total, so to divide it into 4-ounce servings, you would divide 64/4. So there are 16 servings
16
1/2 gallon = (64 fl oz) / (4 fl oz per serving) = 16 servings
It would have to be under 16. Eight ounces is considered a serving of water, and there are 128 ounces in a gallon. That divides out to 16 servings. Now, milk has fat, protein, and vitamins in it, not just water, so you would have to get at least a little less water than 16 servings.
16 8-ounce servings per gallon. (1 gallon is 128 fl oz.)
4 servings
64 fl oz / 4 fl oz = 16 servings
16
16
64
32