Outsourcing (Make-or-Buy) Decision Mountain Air Limited manufactures a line of room air purifiers. Management is currently evaluating the possible production of an air purifier for automobiles. Based on an annual volume of 10,000 units, the predicted cost per unit of an auto air purifier follows. Direct materials $ 9.00 Direct labor 1.40 Factory overhead 10.00 Total $ 20.40 These cost predictions include $80,000 in fixed factory overhead averaged over 10,000 units. The completed air purifier units include a battery-operated electric motor, which Mountain Air assembles with parts purchased from an outside vendor for $2.00 per motor. Mini Motor Company has offered to supply an assembled battery-operated motor at a cost of $5.50 per unit, with a minimum ann