Practice Problem 4 Practice Problem 4 (Contd.) Kenichi Kaneko is the manager of a production department which uses 400 boxes of rivets per year. To hold down his inventory level, Kenichi has been 1 \"\"9 $850 2 100 to 999 $8.00 ordering only 50 boxes each time. However, the 3 1,000 or more $7.50 suppliers of rivets now is offering a discount for higher (a) What is the optimal order quantity and the quantity orders according to the given price schedule. resulting total cost (including purchase cost)? (b) With this order quantity, how many orders must The company uses an annual holding cost rate of 20% of . . _ . . , . be placed per year? What IS the time Interval the price of the Item. The total cost assouated With between orders? placing an order is $80 per order