Afarming cooperative mixes two brands of cattle feed. grainx costs $25 per bag and contains 2 units of protein, 2 units of carbohydrates, and 2 units of fat. good-grass costs $20 per bag and contains 1 unit of protein, 9 units of carbohydrates, and 3 units of fat. find the number of bags of each brand that should be mixed to minimize cost of each animal needs a minimum of 12 units of protein, 36 units of carbohydrates and 24 units of fat