Suppose an animal feed to be mixed from soybean meal and oats must contain at least 100 lb of protein, 20 lb of fat, and 12 lb of mineral ash. Each 100-lb sack of soybean meal costs $20 and contains 50 lb of protein, 10 lb of fat, and 8 lb of mineral ash. Each 100-lb sack of alfalfa costs $11 and contains 30 lb of protein, 8 lb of fat, and 3 lb of mineral ash. How many sacks of each should be used to satisfy the minimum requirements at minimum cost