A boy is leaving his house to go to class, and as he leaves he looks in the mirror and checks the time. Since the mirror is not digital and has no numbers, he mistakes it for correct (when in actualitly it was the mirror image.) He rides his bike for 20 minutes, and when he enters the room, he looks at the clock and notices it is 2 and a half hours later then when he thought he left. What time did he arrive at class?
(it might help if you draw a picture )