Question:
Two types of vehicle use the university central bus station: Uni-link buses and National Express coaches.
a) On average, a National Express coach arrives every two hours. What is the probability that only one bus will arrive in a four hour period?

b)On the U1 Uni-link bus route, buses either go to the airport or to the docks. Other Uni-link routes do not go to the airport. At the bus station, half
of the U1 buses which arrive are going to the airport. At midday, 10% of the Uni-link buses are full. Of these particular buses, 30% are airport buses on the U1 route. U1 buses make up 40% of the Uni-link arrivals at the bus station. What is the probability that a bus is full at midday, given that it is an Airport U1 bus?
c) On average, a certain number, k, of National Express coaches go to Bournemouth every day. It is found that the probability of n coaches going
to Bournemouth in a day is e^(-k) . What is n?