9) Consider an Erlang loss system. The average processing time is 6 minutes. The average interarrival time is 4 minutes. The number of servers is 4. What is the utilization of the servers? 10) A product's demand per period follows a normal distribution with mean of 60 and standard deviation of 10. The lead time is 2 periods. What order-up-to level should be used to achieve at least a 95% in-stock probability? Use Table 14.1. 11) Store A uses the newsvendor model to manage its inventory. Demand for its product is normally distributed with a mean of 500 and a standard deviation of 150. Store A purchases the