A1. Miss Dombo, a Ticketing Manager with an Airline

ying international routes, has realised
that not all passengers show up for their reserved seat. It is clear to her that each passenger's
behaviour is independent of the other. Having �xed the chances of a passenger not showing
up at ten in a hundred, she then instructs the Ticketing O�ce to sell 123 tickets for a
ight
that holds only 118 passengers. On the basis of this information, compute, for a particular

ight, the probability that
(a) every passenger who shows up can take the
ight. [7]
(b) the
ight departs with empty seat(s). [5]
(c) the
ight departs with exactly �ve empty seats. [3