Henrique Correa's bakery prepares all its cakes between 4 AM and 6 AM so they will be fresh when customers arrive. Day old cakes are virtually always sold, but at a 50% discount off the regular $10 price The cost of baking a cake is $7, and demand is estimated to be normally distributed, with a mean of 25 and a standard deviation of 6. What is the optimal stocking level?