31 An animal feed company is developing a new puppy food. Their nutritionists have specified that the mixture must contain the following components by weight: at least 16% protein, 13% fat, and no more than 15% fiber. The percentages of each nutrient in the available ingredients, along with their cost per pound, are shown in the table at the top of this page.

What is the mixture that will have the minimum cost per pound and meet the stated nutritional requirements?

INGREDIENT NUTRIENT BEEF PORK CORN LAMB RICE CHICKEN Protein (%) 16.9 12.0 8.5 15.4 8.5 18.0 Fat (%) 26.0 4.1 3.8 6.3 3.8 17.9 Fiber (%) 29.0 8.3 2.7 2.4 2.7 28.8 Cost ($/lb) 0.52 0.49 0.20 0.40 0.17 0.39