Please answer question a,b,c to get a thumb up

Question#3 [10 points] Nova Inc. will introduce a new product line. A typical product will ship an average of 40 units per day from the firm's central distribution centre. Historical sales patterns indicate that the standard deviation of daily sales should be approximately eight units. The typical logistics performance cycle (i.e., delivery lead time) for comparable products has been a mean of 10 days and a standard deviation of six days. Currently, Nova Inc. plans to keep a service level of 95% and replenish the plant's inventory by 300 units. Your task is to determine the inventory implications of the new product. (Use MS Excel's NORMSINV function to find the exact safety stock factors.) a) Calculate the average inventory according to the current plan. b) Keeping all else the same, calculate the average inventory when the logistics performance cycle standard deviation is halved (i.e., reduced by 50%). c) Briefly comment on the differences in values you found in a) and b) and why this might be the case