need some help with these 4 questions

37. A dry cleaning firm uses an average of 20 gallons of cleaning fluid a day. Usage tends to be normally distributed with a standard deviation of two gallons per day. Lead time is four days, and the desired service level is 92 percent (Z=1.41). What amount of safety stock is appropriate if cleaning fluid is reordered every 45 days? A. 7.36 gallon B. 12.05 gallon C. 15.51 gallon D. 19.74 gallon E. 21.36 gallon 38. Continue with Question 37. All parameters in Question 37 are kept the same except that a reorder point policy is used to manage the inventory. What amount of safety stock is appropriate if a fixed order size of 600gallons is used? A. 3.74 gallon B. 5.64 gallon C. 7.36 gallon D. 15.51 gallon E. 21.36 gallon 39. A bakery's use of corn sweetener is normally distributed with a mean of 80 gallons per day and a standard deviation of four gallons per day. Lead time for delivery of the com sweetener is normal with a mean of six days and a standard deviation of two days. If the manager wants a service level of 99 percent (Z=2.33), what reorder point should be used? A. 571.3 gallon B. 853.5 gallon C. 933.7 gallon D. 1024.3 gallon E. 1141.5 gallon 40. A company uses FOI policy to manage its replenishment process. They review their inventory and place new order every two weeks. The daily demand is 10 units. Lead time is 5 days. For a specific ordering date, their on hand inventory level was 36 , and they decided to order 204 units. Which of the following is their safety stock? A. 19 B. 50 C. 86 D. 140 E. 190