This is the scenario where you know nothing else other than you waited 10 minutes To make the math work, I think you need to make several other assumptions. D

This is the scenario where you know nothing else other than you waited 10 minutes To make the math work, I think you need to make several other assumptions. Don't you also have to know that that ten minutes you sampled are representative? That the events (if they did occur) are independent? It seems odd that you'd in a situation where you can rely on specific assumptions like these while also believing that buses and aliens are equally likely to appear.