Karin arrives at the post office, which opens at 9:00 a.m., at 9:05 a.m. She finds two cashiers at work, both serving one customer each. The customers started being served at 9:00 and 9:01, respectively. The service times are independent and Exp(8)-distributed. Let Tk be the time from 9:05 until service has been completed for k of the two customers, k = 1, 2. Find E Tk for k = 1 and 2.