Suppose that the service time at a store with only, onecheck-out counter is Exponentially distributed, with a mean time of10 minutes.
a) What is the probability that a customer who is first in linenow will spend more than 15 minutes waiting in the check-out line?(Solve using Exponential distribution and then using Poisson.)
b) A customer has already been waiting in the line for more than10 minutes. What is the probability that this customer will stillbe at the store in more than 15 minutes from now?
c) What is the probability of spending less than a half an hourat the check-out? (Solve using two different time units.)
