Victorian playhouses

Playhouse World is distributor for a Victorian-style playhouse manufactured in Thailand. If the firm is out of stock of this playhouse, it offers customers a discount of $50 for each week they must wait for delivery. The administrative cost of processing a backorder is estimated to be $10. The playhouses cost the firm $3500 each and sell for $6000 each. Demand averages two units per month. Due to the fairly high cost of preparing customs documents, the cost of placing an order is estimated to be $1500 and an order takes approximately one month to arrive. Playhouse World estimates that the annual holding cost for the Victorian style playhouse is $450. The company wishes to determine how many Victorian playhouses it should order and the approximate percentage of customers who will have to wait for delivery.