You have two ways to drive home from school: Route A is usually quicker; Route B is
scenic but slower. You choose Route A on 60% of your days and this gets you home by
4:00 P.M. 80% of the time. When you choose Route B you get home by 4:00 P.M. only
30% of the time. What is the probability that you choose Route B and get home by 6:00
P.M.?