Northern Production Company has 200 labor-hours available. There is no limit on machine-hours. Northern can sell all of Y it wants, but it can only sell 45 units and 20 units of X and Z, respectively. Product X Product Y Product Z Contribution margin per unit $30 $20 $24 Labor-hours per unit 4 5 4 Machine-hours per unit 10 8 2 A ) What is the contribution margin per labor-hour for product Y? B) To maximize profits, how many units of each product should Northern produce?