Question A.: A Burger King processes on average 1200 customers/day (over the course of 15 h). At any given time, 60 customers are in the store. Customers may be waiting to place an order, placing an order, waiting for the order to be ready, eating, and so on. What is the average time that a customer spends in the store?

Question B.: In A above, it is mentioned that at any given time, one can find 60 customers in the store. How often can the manager of the store expect that the entire group of 60 customers would be entirely replaced?