An airline knows from past experience that 95% of passengers who buy tickets will not miss a given flight. The planes for this flight have 100 seats and the airline decides to sell 105 tickets. Use a Poisson approximation to compute the probability that more than 100 people would show up for the flight. If the airline wants to make sure that this kind of over-booking does not happen for more than 5% of the flights, how many tickets should they sell?
I am not sure how to go about this problem. Any help would be appreciated.