ose that the weight (in pounds) of an airplane is a linear function of the total amount of fuel (in gallons) in its tank. When graphed, the function gives a slope of 6.4. See the figure below. 50 gallons of fuel in its tank, the airplane has a weight of 2220 pounds. What is the weight of the plane with 20 gallons of fuel in its tank? Airplane weight (in pounds) 2220 50 Amount of fuel (in gallons) pounds x