Customers arrive at Lily's Barber Shop during a day in any particular business hour according to a Poisson distribution with a rate of = 2 per hour. Now the shop has two barbers who can each service a customer in exactly 15 minutes. Suppose a customer, Lisa, arrives at 3:00pm and finds both barbers idle.

17) (5 points) The probability that we will observe customers waiting before 3:15pm is:_______________. (Round your answer to four decimal places.)

18) (5 points) The probability that Lisa will find the shop empty when she leaves is: _________________. (Round your answer to four decimal places.)