BLAKJAC
BLAKJAC
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March 25th, 2015 at 7:28:16 AM permalink
Dear Wizard,
I have been playing casino blackjack nearly weekly for several years. Until this week, the most consecutive blackjacks I had seen dealt (it was to me) was 4. This week I was dealt 5 consecutive blackjacks. Neither the dealer, the other players, nor the floor had ever seen this happen. Just how rare is this occurrence?
Love your work...have lurked around your site for years!
Lisa
Dieter
Administrator
Dieter
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March 25th, 2015 at 8:13:53 AM permalink
How many decks of cards were in play?
May the cards fall in your favor.
AxelWolf
AxelWolf
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March 25th, 2015 at 8:50:55 AM permalink
Quote: Dieter

How many decks of cards were in play?

Let the games begin.
♪♪Now you swear and kick and beg us That you're not a gamblin' man Then you find you're back in Vegas With a handle in your hand♪♪ Your black cards can make you money So you hide them when you're able In the land of casinos and money You must put them on the table♪♪ You go back Jack do it again roulette wheels turinin' 'round and 'round♪♪ You go back Jack do it again♪♪
AxelWolf
AxelWolf
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March 25th, 2015 at 8:51:02 AM permalink
Quote: Dieter

How many decks of cards were in play?

Let the games begin.
♪♪Now you swear and kick and beg us That you're not a gamblin' man Then you find you're back in Vegas With a handle in your hand♪♪ Your black cards can make you money So you hide them when you're able In the land of casinos and money You must put them on the table♪♪ You go back Jack do it again roulette wheels turinin' 'round and 'round♪♪ You go back Jack do it again♪♪
rsactuary
rsactuary
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March 25th, 2015 at 9:47:43 AM permalink
Quote: AxelWolf

Let the games begin.



You can say that again!
rdw4potus
rdw4potus
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March 25th, 2015 at 10:07:02 AM permalink
With replacement after each hand, it looks to me like the odds are about 1:4.2MM.
"So as the clock ticked and the day passed, opportunity met preparation, and luck happened." - Maurice Clarett
BLAKJAC
BLAKJAC
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March 25th, 2015 at 10:19:20 AM permalink
Sorry, folks...I should have noted that there were 8 decks in play.
Romes
Romes
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March 25th, 2015 at 12:18:21 PM permalink
Welcome to the forums, Lisa.

Odds of Blackjack... 2* (Odds of Ace)*(Odds of 10 valued card). For 8 decks:

(Odds of Ace, in 8 decks) = 32/416 = 0.0769
(Odds of '10', in 8 decks) = 128/415 = 0.3084

Odds of getting 1 Blackjack = 2 * .0769 * .3084 = .0474, or 4.74%.

Now, we're going to assume after every hand the dealer reshuffled the 8 decks. I know they don't do that, and the math would only differ slightly, but this should be a fairly close estimate...

Odds of getting 5 Blackjacks in a row = .0474^5 = 2.393*e-7 = .0000002393, about 1 in 4.2 million =)

The Wizard Says the odds of a blackjack for n decks is: 2*(4/13)*(4n/(52*n-1))

Simplifying the Wizards formula a bit: 32n / 13(52*n-1) = 256 / 5395 = .0475 = 4.75%. If we again assume a shuffled deck each go it would be .0475^5 = 2.418*e-7 = .0000002418, or close to 1 in 4.2 million as previously described.
Playing it correctly means you've already won.
rdw4potus
rdw4potus
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March 25th, 2015 at 12:22:36 PM permalink
Hey Romes - check the decimals on your ace odds...
"So as the clock ticked and the day passed, opportunity met preparation, and luck happened." - Maurice Clarett
Romes
Romes
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March 25th, 2015 at 12:27:33 PM permalink
Quote: rdw4potus

Hey Romes - check the decimals on your ace odds...


lol I knew I'd get called out. As soon as I reviewed and saw "omg 23% chance for BJ?!?!" I was like, okay where's the decimal...
Playing it correctly means you've already won.
rdw4potus
rdw4potus
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March 25th, 2015 at 1:21:13 PM permalink
Quote: Romes

lol I knew I'd get called out. As soon as I reviewed and saw "omg 23% chance for BJ?!?!" I was like, okay where's the decimal...



lol. right? I think there's still one small issue. You need to multiply by 2, since order doesn't matter. odds of 1 BJ are 2* 2.37%...
"So as the clock ticked and the day passed, opportunity met preparation, and luck happened." - Maurice Clarett
Romes
Romes
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March 25th, 2015 at 1:53:29 PM permalink
Quote: rdw4potus

lol. right? I think there's still one small issue. You need to multiply by 2, since order doesn't matter. odds of 1 BJ are 2* 2.37%...


Yeah, I got caught up at work and said F it, I'll leave it wrong (with the Wiz's correct math below it) for an hour or two =P. Ty though for pointing it out, I would hate to have mislead someone with a simple math mistake!
Playing it correctly means you've already won.
GWAE
GWAE
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March 25th, 2015 at 3:12:47 PM permalink
I would be good at math if there weren't letters involved. WTF, why are their letters. I am great at non lettered math.
Expect the worst and you will never be disappointed. I AM NOT PART OF GWAE RADIO SHOW
mrclean
mrclean
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March 25th, 2015 at 3:35:18 PM permalink
Last year I got 5 naturals in a row early in a 8 deck shoe. My first card on the 6th hand was a 10 and I told the dealer, if the phone rings I'm out the door.
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