How can I solve d and e?

Open Question 3 Tax Preparers, Inc. works 250 days per year. The company uses adding machine tape at a rate of eight rolls per day. Usage is believed to be normally distributed with a standard deviation of three rolls during lead time. The cost of ordering the tape is E10, and holding costs are E0,30 per roll per year. Lead time is two days. Fill-in the following table. Question Answer a. Calculate the economic order quantity. b. What are the total annual holding costs of stock? c. What are the total annual ordering costs of stock? d. What reorder point will provide an order-cycle service level of 97 percent? e. How much safety stock must the company hold to have a 97 percent order-cycle service level