The following is an excerpt from a letter to the editor written by Roger Cleary that appeared in the San Luis Obispo Tribune (September 16, 2008): The causes of poor fuel economy have nothing to do with higher highway speeds, notwithstanding all the press hoopla, including the July 19 Miami Herald claim that "There is no question that slower speeds will save gasoline," and the July 3 statement by Drive Smarter Challenge vehicle director Deron Lovaas that, "I'm not sure whether most people make the connection between how fast they drive and how much fuel they use." I decided to gather the speed facts for myself using my Chevy, which comes equipped with a fuel usage driver information center, real-time read out. At a road speed of 17.5 mph, it averages 10 mpg; at 35 mph, it averages 20 mpg; and at 65 mph, it averages 30 mpg, all testing done with engine speed standardized at 2000 rpm. The higher the speed, the better the fuel economy. The faster you drive, the more fuel efficient you become and the more gasoline you save. Notice that the only speeds that the letter writer provides data for are 17.5, 35, and 65 mpg. Studies of the relationship between y = gas mileage and x = speed have suggested that the relationship is not linear, and some have used a quadratic curve to describe the relationship between gas mileage and speed. Write a response to Mr. Cleary that explains how his three observed data points could still be consistent with the statement that higher highway speeds lead to reduced fuel efficiency. Include a graph to support your explanation.