Food and clothing are shipped to victims of a natural disaster. Each carton of food will feed 16 ​people, while each carton of clothing will help 7 people. Each 15​-cubic-foot box of food weighs 40 pounds and each 5​-cubic-foot box of clothing weighs 20 pounds.The commercial carriers transporting food and clothing are bound by the following​ constraints:
​- The total weight per carrier cannot exceed 21 comma 000 pounds.
​- The total volume must be no more than 6000 cubic feet.