Question: Customers arrive at an Internet center at the rate of one every 15 ± 5 minutes. 80% of the customers check simply their email inbox, while the remaining 20% download and upload files. An email customer spends 5 ± 2 minutes in the center and the download customer spends 15 ± 5 minutes. Simulate the service completion of 500 customers. Of these 500 customers, detennine the number of email and download customers and compare with the input percentage.