Homer Tube Inc. manufactures two types of tubing: copper tubing and plastic tubing. Their factory has a capacity to manufacture up to 300 copper tubes and up to 500 plastic tubes per month, but can only manufacture up to a combined total of 700 of both types of tubes per month. Each copper tube takes 4 hours to manufacture and each plastic tube takes 2 hours to manufacture. Homer Tube has budgeted 1,800 hours per month to produce these tubes