If your question is that you have four gallons of cider and you are going to serve it in eight oune cups, will you have enough to serve to 30 people; then the answer is yes. You would have enough to serve 30 peopole 2 servings each and still have cider left.
1 fluid ounce = 0.00625 gallons.
If you assume everyone will have two 6 ounce glasses that would be about 10 gallons
1 fluid ounce contains 0.0078125 US gallons.
You would need 7.5 gallons to get 120 8 ounce servings.
4.05 US gallons.
40 gallons = 5120 ounce
One fluid ounce is 0.0078125 gallon.
(100 people) x (8 oz per person) / (128 oz per gallon) = 6.25 gallons
1 ounce
One gallon = 128 fluid ounces Therefore, there is 1/128 gallons in one ounce. 1/128 = 0.0078125
one tenth
5 US gallons = 5 x 128 ounces = 640 ounces cost of 1 ounce = 130.00/640 = 0.203125