Krouscas Foods makes a special blend of oil that is popular in Greek cooking. They import oil from two vendors and blend it to ensure that the resulting product contains at least 40% olive oil, 20% sunflower oil, and at least 30% corn oil. Vendor 1 can provide an oil containing 50% olive oil, 10% sunflower oil, and 40% corn oil at a cost of $9 per gallon. Vendor 2 can provide an oil containing 20% olive oil, 60% sunflower oil, and 20% corn oil at a cost of $8 per gallon. If Krouscas wants to produce 30 gallons of its special blend of Greek cooking oil at minimum cost, how much oil should it buy from each vendor?

a. Formulate an LP model for this problem.

b. Sketch the feasible region for this problem.

c. Find the optimal solution.