So what you want to do is do long division (using 32.000 divided by 1243.12). You should get this answer:
0.02574
Hope this helped
You need to set up a linear graph. One side with gallons and the other with dollars. Point 1 will be at (1500, 2.10). Point 2 (1300, 2.95). Draw a straight line through these points in your graph and your graph will then give you the answers to your other questions.