https://en.wikipedia.org/wiki/Sleeping_Beauty_problem
An equivalent experiment but with an explanation of the solution: 1) system alerts you 2) system records random number, one or two. you guess what it is. 3) if it were two, it changes to one, waits 5 seconds and alerts you, then you guess what number it was. 4) wait 5 seconds 5) repeat like 100 times or until user wants to stop. 6) you have a look back at the recorded random numbers 7) you realise it's probably usually one so you always guess one now.