... different foods. Each ounce of food X contains 12 units of calcium, 10 units of iron, and 20 units of vitamin B. Each ounce of food Y contains 15 units of calcium, 20 units of iron and 12 units of vitamin B. The minimum daily requirements of the diet are 300 units of calcium, 280 units of iron, and 300 units of vitamin B.
a) Write a system of inequalities describing the different amounts of food X and food Y that can be used.
b) Sketch a graph of the region in part (a)
c) Find two solutions to the system and interpret their meanings in the context of the problem