Alice and Bob each arrive at a party at a random time between 1:00 and 2:00. If Alice arrives after Bob, what is the probability that Bob arrived before 1:30?
I thought that I could create a graph to find the probability of the event occurring, but I'm not exactly sure what to do. I've seen many different variations of this problem, but that only involves Alice or Bob waiting a certain amount of time and then leaving. This, I believe, is a completely different problem. Help is greatly appreciated.