Solve each problem.

An agency wants to ship food and clothing to tsunami victims in Japan. Commercial carriers have volunteered to transport the packages, provided they fit in the available cargo space. Each 20-ft³ box of food weighs 40 lb and each 30-ft³ box of clothing weighs 10 lb. The total weight cannot exceed 16,000 lb, and the total volume must be at most 18,000 ft³. Each carton of food will feed 10 victims, and each carton of clothing will help 8 victims. How many cartons of food and clothing should be sent to maximize the number of people assisted? What is the maximum number assisted?