The gas mileage, m, of a compact car is a linear function of the speed, s, at which the car is driven,
for 40
s 90. For example, from the graph we see that the gas mileage for the compact car is 45
miles per gallon if the car is driven at a speed of 40 mph.
i) Using the two points on the graph, determine the function m(s) that can be used to approximate
the graph.
ii) Using the function from part i, estimate the gas mileage if the compact car is traveling 75 mph. If
necessary, round to the nearest tenth.
iii) Using the function from part i, estimate the speed of the compact car if the gas mileage is 39
miles per gallon. If necessary, round to the nearest tenth.