A store owner purchases boxes of cereal for a price of $3.65 each and sells 4 box of cereal per week. The widgets are offered in cases of 48 each (no partial case shipments are allowed). The retailer's cost of holding one widget in inventory for one year is $0.83. When the retailer purchases widgets, there is a fixed charge of $74 for each order.

How many cases of widgets should the retailer purchase at one time?

Note: Assume there are 52 weeks in a year.