Consider Bob's Burger Barn. Bob has a simple menu: burgers made Bob's way, french fries (one size), and soft drinks (one size). Customers place orders with one cashier who enters the order and collects the payment. They then wait near the counter until the order is filled. The time between customer arrivals during the lunch hour from 11:30 to 1:00 P.M. is exponentially distributed with mean 30 seconds. It takes a uniformly distributed time between 10 seconds and 40 seconds for order placement and payment at the cashier. The time to fill an order after the payment is completed is normally distributed with mean 20 seconds and standard deviation 5 seconds.

a. Build a model of Bob's Burger Barn.

b. Embellish the model for the case where a customer will leave upon arrival if there are more than 7 customers waiting for the cashier.