Answer:
Check the explanation
Step-by-step explanation:
Cost of over reserving full cost tickets, Co = $440 ( empty seats as we cannot get even the discounted revenue)
Cost of under reserving Cu = 770-440 = $330 ( because you sell more discounted tickets)
Now critical ratio = Cu / (Cu+Co) = 330/770 = 0.42857
Now for above critical ratio ,z = -0.18 ( refer standard normal distribution table)
Optimal protection level = mean +z*standard deviation = 100-0.18*25 = 95.5 = 96
The possible costs include: all the above. You may need to provide compensation to passenger and make alternative travel arrangements. Also passenger won't be happy by over booking and their will be loss of good will.