1. If Valdez wants to ensure that his customers wait an average of around 10 minutes, what should be his average service time? Assume that the standard deviation of service time remains at 15 minutes.
2. Customers arrive at an automated coffee vending machine at a rate of 4 per minute, following a Poisson distribution. The coffee machine dispenses a cup of coffee at a constant rate of 10 seconds.
(a) What is the average number of people waiting in line?
(b) What is the average number of people in the system?
(c) How long does the average person wait in line before receiving service?