The Car Lot is a New York car dealership located in a highly visible area along a prominent highway. Fred Barns, owner of The Car Lot, is trying to decide how much front-row space along the highway to devote to each of four different car models. Fred has a maximum front-row space of 200 feet to devote to the four car models. He wants a minimum of 20 feet and a maximum of 80 feet of front-row space for each car model. Appropriate data on the four car models follow: Convertible Truck Sedan SUV Sales price per unit $40,000 $30,000 $60,000 $25,000 Variable costs per unit 32,000 23,000 45,000 16,000 UNITS sold per 10 feet of front-row space per month 10 18 25 The convertible model's monthly contribution per 10 feet of front-row space is calculated to be