abebe wishes to mix two types of food C and D in such a way the vitamin contents of the mixture contain at least 8 units of vitamins C and 11 units of vitamin D. food C costs $60/kg and food D costs $80/kg. Food C contains 3 units/kg of vitamin A 5 units /kg of vitamin B while food D contains 4 units /kg of vitamin A and 2 units /kg of vitamin B. determine the minimum cost of the mixture by graphic model