A doctor’s prescription calls for the creation of pills that contain 12 units of vitamin and 12 units of vitamin E. Your pharmacy stocks three powders that can be used to make these pills: one contains 20% vitamin and 30% vitamin E; a second, 40% vitamin and 20% vitamin E; and a third, 30% vitamin and 40% vitamin E. Create a table showing the possible combinations of each powder that could be mixed in each pill.