The document contains 5 practice problems related to waiting line and queuing models. Problem 1 involves calculating metrics like idle time, busy time, and average wait times for a single-server information desk. Problem 2 calculates total expected costs over an 8-hour day based on the results of Problem 1. Problem 3 examines adding a second server and calculates related metrics. Problem 4 describes the parameters of a coffee machine system. Problem 5 describes the characteristics of a repair shop system with exponential service times and Poisson arrivals.