Phone4U is a new service company that provides European smartphones to American visitors to Europe. The company owns 160 smartphones, which are available in a store located at Charles de Gaulle Airport in Paris. There are, on average, 48 customers per day requesting a smartphone. These requests arrive uniformly throughout the 24 hours the store is open. The corresponding coefficient of variation is 1. Customers keep their smartphones on average 72 hours. The standard deviation of this time is 100 hours. Assume that a smartphone which is returned by a previous customer can be reused immediately by a new customer. Given that Phone4U currently does not have a competitor in France providing equally good service, customers are willing to wait for the smartphones and assume that lines can be infinitely long. The smartphones are given to customers on a first-come-first-served basis.