Pneu Shoe Company manufactures various types of athletic shoes. Several types require a built-in air pump. Presently, the company makes all air pumps it requires. However, management is evaluating an offer from Ram Air Co. to provide air pumps at a cost of $3.60 each. Pneu Shoe's management has estimated that the variable production costs of the air pump total $2.70 per unit and that the company could avoid $27,000 per year in fixed costs if it purchased rather than produced the air pumps