The Gem (TG) is an organic juice bar located in Philadelphia. TG is particularly famous for its protein-smoothies and currently has two smoothie-makers (each is operated by a single employee). Customers arrive at TG with an average rate of 60 customers/hour, and the standard deviation of inter-arrival times is 2 minutes. Furthermore, historical data indicates that the protein-smoothie preparation times are distributed exponentially with a standard deviation of 96 seconds. (a) what is the average waiting time