A bank manager wishes to provide prompt service for customers at the bank's drive-up window. The bank currently can serve up to 10 customers per 15-minute period without delay. The average arrival rate is 28 customers per hour. Let x denote the number of customers arriving per 15-minute period. Assuming x has a Poisson distribution:
Find the probability that 8 customers will arrive in a particular 15-minute period.
Find the probability that there will be customer waiting for service at the drive-up window.