Playing with the pack of cards on my desk, something just happened that I didn't expect!
Look at the deck with the cards face-up. Here's a rule: look at the top card. Draw that many cards from the deck. Repeat until the deck is empty.
I did this, and dealt out exactly the right number of cards (at the end, I had 3 cards left and the top card was a 3).

What's the probability of this happening?

#IDontKnowYet

@christianp If each card appears randomly with replacement (magically?) and you reach a pile with k cards left, let P_k = probability you won. P_k = 0 if k < 0 (you ran out of cards in last draw), P_0 = 1 (you won!), and otherwise P_k = sum_{i=1}^13 P_{k-i}/13. A quick computational experiment shows that for large k like k=52, P_k appears to converge to 1/7.

@11011110 @christianp

Quick question: how do you consider the effect that you only have 4 suits for every card?

@sojournTime @christianp I'm not considering it. That's what I meant about "with replacement". It's an assumption that makes the mathematics easier but also less accurate for the actual problem.

Sign in to participate in the conversation
CleverLibre Social

CleverLibre Social is an inclusive social instance for open discussion, learning, and community.
All cultures welcome.
Hate speech and harassment strictly forbidden.