For a Single-Server, Single-Line, Single-Phase Waiting Line System, Where

Multiple Choice

For a single-server, single-line, single-phase waiting line system, where  represents the mean arrival rate of customers and  represents the mean service rate, what is the formula for the average time spent in the system?

A)  / 
B)  / ()
C) ² / ()
D) 1 / ()
E)  / ()