Tax Pro provides tax-preparation software services to file taxes online. The company offers live expert help for premium customers and promises to connect a customer with an experienced tax professional to answer tax questions. If a tax professional is not available, the customer is notified and the request is placed in a separate call-back queue. The company has 6 experienced tax professionals on call to answer customer questions. During the peak season, they receive on average 20 customer requests per hour. It takes on average 12min for a tax professional to answer a customer question. Q9. What is the average inter-arrival time for customer requests in mins? 3min