1. A tiny branch post office is being constructed at the Smalltown Mall. Post office patrons wait in a single line for the first open window, where 1, 2, or 3 windows are being considered. Assume that this queue is restricted to 2 waiting patrons (not being served) because of space. An average of 15 patrons per hour is expected to enter the post office, and each window will be able to serve an average of 6 patrons per hour. The post office estimates a cost of $1 for each minute a patron waits in line and believes that the cost of keeping a window open is $30 per hour. Interarrival times and service times are exponential. (a) State the applicable queueing model for the possible values of c. (b) How many windows (i.e., the value of c) must be open for a steady state to exist? (c) What is the total expected hourly cost for c=3