Question 3: [12 marks] Lingnan Barkey (LB) sells egg tarts. Historically, LB has observed that hourly demand of egg tarts is normally distributed with a mean of 100 units and a standard deviation of 10 units. The baking time of egg tarts (lead time) appears normally distributed with a mean of 0.5 hours and a standard deviation of 0.1 hours. LB aims to limit the stock out risk during lead time to 10 percent. When should LB start to bake a new batch of egg tarts