I need a step by step hand written solution please :)

In a periodic order system, the lead time for a box of weed killer is 2 weeks. The review period is 1 week. Demand during the protection interval (i.e. review period +lead time) averages 218 boxes, with a standard deviation of 40 boxes. a.) What is the cycle-service level when the target inventory is set at 300 boxes? b.) In the fall season, demand for weed killer decreases but also becomes more variable. Assume demand during the protection interval is expected to decrease to 180 boxes, but with a standard deviation of 50 boxes. What would be the cycle-service level if management keeps the target inventory level set at 300 boxes? C) if the solution is feasible, should the order quantity change