Assignment:
Customers enter the waiting line at a cafeteria on a first come, first served basis in two serving lines.
The arrival rate follows a Poisson distribution, while service times follow an exponential distribution.
If the average number of arrivals is two per minute and the average service rate of three customers per minute, what is the average time a customer spends in the queue?
Provide complete and step by step solution for the question and show calculations and use formulas.