Poker Dice Problem. Can You Help?
By poker_boy | 3 CommentsLeave a Comment
Last updated: Monday, June 21, 2010 | 79 Views Tags: , ,

A poker question that should definitely interest you all this week

Question: 5 dice displaying A,K,Q,J,10,9
Punter bets on 2 of the 6 selections
all 5 dice thrown
if at least 1 of each of the punter’s selections are showing they are paid 2/1 and receive 3 times their stake .
Any other outcome and stakes are forfeited.
What is the house percentage?
The book answer is 12.3% to the house!
I think it is about 1.5% to the house.
Can someone clarify please?
Thank you.
Answer: So if the punter bets on 2 selections, he’ll loose if non of the 5 dice shows them.

For each dice the probability of not showing the punters predictions is 4/6 = 2/3.
So the probability that none is shown is (2/3)^5 = 32/243

Let’s call A and B Punter’s bets.

The probability that only A shows up and not B is

P( B never shows up) - P(A and B never show up) = (5/6)^5 - (4/6)^5 =
(3125 - 1024)/7776 = 2101/7776

So the probability of losing is 2(2101/7776) + 32/243 = (2101 + 512)/ 3888 = 2613 / 3888.

The probability of winning is 1275/3888 and the expected return is 1275/1296 = 425/432.

So the house takes 7 / 432, which proves the book messed up and you are right.

Clearly the author never gambles. No player would risk a bet against a house taking 12.3%

Comments

3 comments
  1. Jhon Smith
    June 21, 2010

    No

    Leave a reply
  2. calimero
    June 21, 2010

    Sorry, Ken, j’ai toujours été nulle en maths mais j’étoile ta question.
    Cheers !

    Leave a reply

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