3. All transport vehicles that travel on a certain road must pass a weight control. Vehicles arrive at this control according to a Poisson Process with an average rate of 20 vehicles per hour. Currently, the waiting vehicles form a single queue and there are two checkpoints, each attended by an employee. These employees take exponential time to attend to each vehicle with an average of 5 minutes. Due to space, there cannot be more than 4 vehicles queued. a) Determine the queuing model and build the rate diagram. (0.75 points) b) Calculate the employee idle time, the average time a truck spends in the system, the average number of trucks queued and the average number of trucks that due to lack of capacity would leave the weight control center. (1 point)