A nutritionist, working for NASA, must meet certain minimum nutritional requirements and yet keep the weight of the food at a minimum. He is considering a combination of two foods, which are packaged in tubes. Each tube of food A contains 4 units of protein, 2 units of carbohydrates, and 2 units of fat and weighs 3 pounds. Each tube of food B contains 3 units of protein, 6 units of carbohydrates, and 1 unit of fat and weighs 3 pounds. The requirement calls for 48 units of protein, 42 units of carbohydrates, and 18 units of fat. How many tubes of each food should be supplied to the astronauts? The number of tubes of food A is (Simplify your answer.) The number of tubes of food B is (Simplify your answer.)