You record the total fuel used at various times during the trip and make the graph below, showing amount of fuel used as a function of time. X 15 10 10 15 20 t (hours) Using only these two graphs, estimate your instantaneous velocity 15 hours after the start of the trip. Explain how you arrived at that value. Hint #1: You'd be wasting your time and missing the point if you tried to find formulas for these graphs. Use the graphs. You'll probably want to print them onto paper. Hint#2: Pay attention to the units.