Consider an airport where taxis and customers arrive (exponential inter-arrival times) with respective rates of one and two per minute. No matter how many other taxis are present, a taxi will wait. If an arriving customer does not find a taxi, the customer immediately leaves. a. Model this system as an M/M/1 queue. ( Hint: Think of the taxis as the “customers.”) b. Find the average number of taxis that are waiting for a customer. c. Suppose all customers who use a taxi pay a $10 fare. During a typical hour, how much revenue will the taxis receive?