Char Coal is an importer & supplier of coal for big industries like cement plants. It recently received an order for 1000 tons of coal with the following specifications: Calorific Value of at least 190 Kcal per ton, Sulfur content of less than 6 kilos per ton. To meet these specifications, Char Coal blends three (3) kinds of coal that it imports with the below-listed specifications.

Coal Type A B C _

Calorific Value (Kcal/ton) 200 180 182

Sulfur Content (kilos/ton) 5 6 9

Minimum Order Quantity 300 none none

Set-up cost to ordering $ 6,000 $ 5,000 $ 4,000

Unit Cost/ton $ 500 $ 450 $ 380

As they supply blended coal, delivery to the customers must have at least two (2) types of coal blended. Additionally, management has decided to either order at least 400 tons of Type B or at least 450 tons of Type C. Formulate an ILP Model of the foregoing that will minimize their cost.