Suppose a company wants to ship four types of products utilizing a small cargo ship. The weight and volume capacities of the ship are: < Compartment 1. Front 110 Weight (tons) Volume (cu. ft.) < 6,000 < 9,000 7,500 2. Centre 125 3. Back 75 The products are: < Products Weight (tons) Volume (cu. ft./ton) Revenue (dollars/ton) < 1 160 48.6 < 2 < 175 60.0 < 3 < 600 < 4.1 4 < 100 < 55.0 700 < 750 250 < 300 < The firm wants to determine how much weight of each type of product is to be loaded in each compartment such that total revenue is maximized without violating weight and volume constraints. The products must be loaded such that the "trim of the ship is preserved. This means that the ratio of loaded weight in a compartment to the weight capacity in that compartment must be identical for all three compartments. Formulate this problem as an LP model.