$1.[25$ Points Total$]$ Two cell phone diagnostic stores are located next to each other in a mall. Each has one employee and enough space to accommodate $4$ customers; any potential customer who finds a store full will not wait. Store A charges $$11$ per customer and takes an average of $12$ minutes to complete the diagnostic service. Store B charges $$5$ per customer and takes an average of $6$ minutes to complete the diagnostic service. An average of $10$ potential customers per hour arrive at each store. Of course, a potential customer becomes an actual customer only if they find the store isn't already full when they arrive. Assuming that interarrival times and diagnostic service times are exponential, how much money will each store earn per hour? Which store will earn more money?