The NWB Bank operates a drive-up teller window that allows customers to complete bank transactions without getting out of their cars. On weekly mornings, arrival to the drive-up teller occur at random, with a mean arrival rate of 24 customers per hour.
a) Assume that the Poisson probability distribution can be used to describe the arrival process. Compute the probability that exactly 3 customers will arrive during a 5-minute period.
b) Delays are expected if more than 3 customers arrive during any 5 minute period. What is the probability that delay will occur?