Sharp, Inc., a company that markets painless hypodermic needles to hospitals, would like to reduce its inventory cost by determining the optimal number of hypodermic needles to obtain per order. The annual demand is 1,000 units; preparation or ordering fee is $10 per order; and the holding cost per unit per year is $0.50. The company has a 250-day work year and wants to find the number of orders, the expected time between orders, and determine the combined annual ordering and holding cost.