A manufacturing plant makes parts of a machine with a productivity of 10 parts/hour. A quality inspector then inspects and tests the parts. The quality inspector can inspect 5 parts an hour. Twenty parts are then used to assemble the machine which takes one hour. How long will it take to make, inspect and test 80 parts? Draw a CPM node diagram showing relationship among the three activities. Show how you can optimize the schedule. Assume 5 day work week and 8 hours work day. (show detail calculation)