Inventory turnover and days of supply - McDonald's fast-food

The McDonald’s fast-food restaurant on campus sells an average of 4,000 quarter-pound hamburgers each week.  Hamburger patties are resupplied twice a week, and n average the store has 350 pounds of hamburger in stock.  Assume the hamburger costs $1.00 a pound.  What is the inventory turnover for the hamburger patties?  On average, how many days of supply are on hand?