A corporation wants to lease a fleet of 12 airplanes with a…

A cоrpоrаtiоn wаnts to leаse a fleet of 12 airplanes with a combined carrying capacity of 220 passengers. The three available types of planes carry 10, 15, and 20 passengers, respectively. If the 10 passenger plane costs $8000 to lease, the 15 passenger plane costs $14000 to lease, and the 20 passenger plane costs $16000, then how many of each type should be leased to minimize costs? (Be very careful this is a different problem from the review).