AJ Company makes three products. Current selling price per unit, variable cost per unit, and machine hours required are as follows: Products X Y Z Current selling price per unit $20 $30 $20 Variable cost per unit 10 18 12 Machine hours required for each unit 2 3 4 The company has a maximum of 1000 machine hours available per month. Assume the company produces all products; find the total contribution margin per hour.