Ms. Rehana needs to travel from Town A to Town C by train. The train from Town A to Town B takes 1 hour and 20 minutes. Trains leave Town B for Town C every hour at 9:00 am, 10:00 am, 11:00 am, and so on. Ms. Rehana leaves Town A at 8:00 am and arrives at Town B at 9:40 am.

If Ms. Rehana leaves Town A at 8:00 am, how long would she have to wait for the train at Town B if she takes the first available train after her arrival?