Q1-57 Cathy Gwynn for a class project is analyzing a "Quick Shop" grocery store. The store emphasizes quick service, a limited assortment of grocery items, and higher prices. Cathy wants

to see if the store hours (currently 0600 to 0100) can be changed to make the store more profitable. The cost of the groceries sold averages 65% of sales. The incremental cost to keep the store open,including the clerk's wage and other operating costs, is $23 per hour. To maximize profit, when should the store be opened, and when should it be closed?