Problem 6. (10 pts) Bob arrives at a point with 3 roads. The first road brings him back to the same point after 1 hours of walk. The second road brings him back to the same point after 6 hours of walk. The last road leads to the city after 2 hours of walk. There are no signs on the roads. Assuming that Bob chooses a road equally likely and has no memory of previous choices at all times. What is the expected hours of time that Bob arrives to the city