The title says pretty much all. The event is fully random, it has the same chance any minute, it can happen multiple times at the same minute. How is it possible to calculate that?
I made a simulation code in c++, which says 78%, is that good answer? https://gist.github.com/bakaiadam/4f4732f4147fc3a5c68f121bf57b919f
Edit: since people say it's not clear what I mean and I'm not really familiar with random distribution types, I tell you the concrete example that I was thinking about: My idea came from seeing group of people passing in a forest path. Let's say i have been there for 2 hours and saw 2 group of people. What is the probability that i will see at least 1 group of people in the next 10 minutes? Obviously there can be more than one group of people passing at the same minute, and obviously their chance to be there is independent from each other.