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