An average of 20 new orders are started through a certain factory each month. on average, an order consists of 50 parts to be processed through 10 machines in the factory. the operation time per machine for each part = 15 min. the nonoperation time per order at each machine averages 8 hours, and the required setup time per order at each machine = 4 hours. there are 25 machines in the factory, 80% of which are operational at any time (the other 20% are in repair or maintenance). the plant operates 160 hours per month. however, the plant manager complains that some overtime machine-hours must be authorized each month in order to keep up with the production schedule. a. what is the manufacturing lead time for an average order? b. what is the plant capacity (on a monthly basis) and how much overtime should be authorized? c. what is the utilization of the plant? d. determine the average level of work-in-process (number of parts-in-process) in the plant.