JD Precision Parts is a firm that supplies parts and components to auto manufacturers. Because orders received from manufacturers are for different parts, JD must set up its production process to make each order. The following table shows the list of orders that JD has received from eight different manufacturers. The table also depicts the number of parts in each order and the time to make each part. Number of Order parts Setup time (days) Part process time (minutes) 1 9883 1 0.34 234567 5452 0.8 0.81 2000 0.5 0.6 6272 1.2 0.75 2400 0.4 1.12 12000 1.5 0.14 5648 1 0.51 8 3508 0.2 0.52 JD cannot set up its operations for next order until the production of the last order is completed. Also, the production system cannot be used during the set up operations. The plan is to process all these orders in JD's plant in Detroit. a. In what order should JD make and deliver these orders to minimize the average waiting time of the manufacturers? What is the minimum average waiting time? JD has already purchased the material used to make all eight orders. Thus, it will be facing a large inventory holding cost if it does not finish these orders fast. Holding each part in order 1 as inventory (in form of raw material, WIP, or finished goods) in each day costs JD about $0.01. This number is $0.09 for each part in order 2; $0.05 for order 3; $0.04 for order 4; $0.02 for order 5; $0.06 for order 6; $0.07 for order 7; and $0.03 for each part in order 8. b. An order cannot be shipped to a manufacturer until all parts in the order are completed. In what sequence should JD process the orders to minimize its total inventory holding cost of these eight orders?