An urn contains 5 black and 20 white marbles. They are to be drawn one at a time until all of one color has been exhausted.
What is the probability that the color of the first draw correctly predicts the first color exhausted?
(In reply to re: re. difficulty level
I have read your remarks attentively and feel convinced that fighting over D levels should not be exaggerated.
Still, whenever it was done by me, it was done to the merit of the issue, never for other reason.
In the future I'll try to place my remarks only in extreme cases.