Problem D A mail order house uses 20,000 specialty boxes a year. Annual holding costs 2.00 per box Ordering cost $2.00 per order Their vendor has provided the following price schedule: Number of Price per boxes box 1-499 $ 3.00 500-999 $ 2.95 1,000-1,4992.90 1,500 or more 2.85 9 What is the optimal order quantity for the mail house? 10 What is the total overall annual cost at the optimal order quantity