I need some help with these questions please, and would you show how you got the answer to them so I can learn how to do what you did

Scenario 2: A supplier sells a popular auto part to car dealers. The weekly demand is approximately normal with the historical distribution of DN(63,25) units over a 45-week operating year. Currently, the supplier pays $26 for each unit and sells each for $41. In addition, they estimate that the annual holding cost is 30 percent of the unit's cost (to the supplier). It costs approximately $25 to place an order (managerial and clerical costs). Assume a constant, three-week lead time. 6. What is the annual inventory cost under the EOQ? 7. What is the safety stock required per order under the optimal service level