a store has two types of animal feed available. type a contains pounds of oats and pounds of corn per bag. type b contains pounds of oats and pounds of corn per bag. a farmer wants to combine the two types so that the resulting mixture has at least pounds of oats and at least pounds of corn. the store only has bags of type a feed and bags of type b feed in stock. type a costs per bag, and type b costs per bag. how many bags of each type should the farmer buy to minimize her cost?