A truck has a minimum speed of 13 mph in high gear. When traveling x mph, the truck burns diesel fuel at the rate of 0.0027227(784x + x)gal/mile. Assuming that the truck can not be driven over 64 mph and that diesel fuel costs $1.96 a gallon, find the following: a. The steady speed that will minimize the cost of the fuel for a 570 mile trip.
b. The steady speed that will minimize the total cost of the trip if the driver is paid $12 an hour.
c. The steady speed that will minimize the total cost of a 540-mile trip if the driver is paid $20 an hour.