An animal feed to be mixed from soybean meal and oats must contain at least lb of protein, lb of fat, and lb of mineral ash. Each sack of soybeans costs and contains lb of protein, lb of fat, and lb of mineral ash. Each sack of oats costs $ and contains lb of protein, lb of fat, and 1 lb of mineral ash. How many sacks of each should be used to satisfy the minimum requirements at minimum cost?