Acme Parts runs a small factory and employs workers who are paid one of three hourly rates depending on their shift: first shift, $17 per hour; second shift, $18.50 per hour; third shift, $22 per hour. Each factory worker might work any number of hours per week; any hours greater than 40 are paid at one and one-half times the usual rate. In addition, second- and third-shift workers can elect to participate in the retirement plan for which 3% of the...