Consider the following two queuing systems:

* system 1 has two separate queues each with a single server with exponential service times 12 customers/hour and in each queue, customers arrive at a rate 10 customers/hour (Poisson distributed)

* system 2 has a single queue but two identical parallel servers, each server operating at an exponential rate 12 customers/hour, and customers arrive in the queue at a rate 20 customers/hour (Poisson distributed)

Using appropriate queuing models, evaluate the performance of both systems and calculate the average waiting time for a customer; the average number of customers in a queue and in the system, and the average server utilisation. Which system performs best?