Answer:
What is the question?
Explanation:
If its how much will it cost to get ____ gallons
Just multiply the number of gallons you want and 3.50 (the price)
Again, I don't really know what your question is, but I'm saying this so that if what I put up there is actually what your question was, you don't have to make another one. (I'm not sure if you can edit questions or not.)