Target is trying to decide on how many units of Xbox one S to purchase for the holiday season. One unit of Xbox one S retails at $190.00. Microsoft, manufacturer and supplier of the Xbox one S to B&N sells a unit to Target for $170.00. Target will dispose of all of the unsold units of the Xbox one S at 30% off the retail price, at the end of the season. Target estimates that demand for this book during the holiday season is normally distributed with a mean of 100 and a standard deviation of 42. a. How many units of Xbox one S should Target order to maximize his expected profit?