Braun's Brakes manufactures three different product lines, Model X, Model Y, and Model Z. Considerable market demand exists for all models. The following per unit data apply: Selling price direct materials direct labor ($12/labor hour) Model X Model Y Model Z 50 65 70 6 6 12 12 12 4 8 24 24 co fixed support costs 10 10 10 10 10 What is the contribution margin per labor hour of the product that should be produced when there is a limited number of labor hours available? variable support costs ($4/ machine hour)