Advanced Technologies (AT) produces two compression machines that are popular with manufacturers of plastics: no. 165 and no. 172. Machine no. 165 has an average selling price of $31,400, whereas no. 172 typically sells for approximately $28,200. The company is very concerned about quality and has provided the following information: No. 165 No. 172 Number of machines produced and sold 230 235 Warranty costs: Average repair cost per unit $ 970 $ 420 Percentage of units needing repair 60 % 10 % Reliability engineering at $185 per hour 1,670 hours 2,035 hours Rework at AT's manufacturing plant: Average rework cost per unit $ 1,970 $ 1,670