4. (15 points) Alsat airlines serves the route between Istanbul and Izmir with a 100-seat aircraft. Three fare classes are available at 100 TL, 200 TL and 400 TL. The demands for the three fare classes are mutu- ally independent and normally distributed. The demand for the most expensive ticket has mean 20 and standard deviation 5, the demand for the 200 TL fare has mean 40 and standard deviation 12 and for the 100 TL fare has mean 80 and standard deviation 20. It is assumed that the 100 TL booking requests arrive before the 200 TL requests which arrive before the 400 TL booking requests. (a) (10 points) Find the optimal protection levels using the EMSR-b algorithm. (b) (2 points) Assume that a booking limit of 40 is employed for the 100 TL fare and that 55 booking requests arrive for this fare? What is the optimal booking limit for the 200 TL fare? 2