Find the safety stock required at 1 (day) combined standard deviation under conditions of demand and performance cycle uncertainties

Scorekeeper, Inc. manufactures stadium scoreboards. The daily demand distribution is a normal distribution with the mean of 6 units and the standard deviation of 1.81. Also the performance cycle is a normal distribution too with a mean of 12 days and the standard deviation of 1.10. Answer the following two questions.

a. Find the safety stock required at 1 (day) combined standard deviation under conditions of demand and performance cycle uncertainties.

b. If the typical order quantity is 36 units, find the average inventory at 3 standard deviations under demand and performance cycle uncertainty.