3. Suppose you take a car trip, traveling east along a very long highway, starting at time : = 0. Let x 1 be the number of gallons of gasoline used during the first : hours, and let s(t be the distance traveled in that time. Because you're using very cheap gasoline that's not good for the engine, your fuel efficiency (measured in miles/gallon) decreases as fuel is consumed. The graph of fuel efficiency as a function of gasoline used is shown in the graph below. 25 ds dx 101 10 x (gallons) 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. 15 X 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