Date: 9/03/2013 23:16:55
From: OCDC
ID: 277364
Subject: Playing cards

How many 5-card combinations are there in a single deck of cards?
How many in two decks?

Please show working.

(This amn’t anyone’s homework, but I was too tired to work it out myself. I see that Mr Turing is back; please bump it for him if no-one else cares.)

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Date: 9/03/2013 23:27:34
From: esselte
ID: 277371
Subject: re: Playing cards

Isn’t it just 5^52=2.22044046e+36? ie a fair few.

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Date: 9/03/2013 23:35:09
From: esselte
ID: 277372
Subject: re: Playing cards

Wait, it depends on whether the order that the cards is important or not?

If its not important, it would be 52 × 51 × 5 = 13,260.

I think… But I don’t know. I not good at maths. Shouldn’t have said anything. Forget i was here, please. Sorry :)

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Date: 9/03/2013 23:35:20
From: diddly-squat
ID: 277373
Subject: re: Playing cards

1 deck —> nCr 52 5 = 2,598,960
2 deck —> nCr 104 5 = 91,962,520

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Date: 9/03/2013 23:35:21
From: sibeen
ID: 277374
Subject: re: Playing cards

52!/5!(52-5)!

= 52!/(5! *47!)

err, get out mathcad…2598960

For the two packs it will be 104!/ 5!(104-5)! = 104!/(5!*99!) = 91962520

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Date: 9/03/2013 23:36:55
From: esselte
ID: 277375
Subject: re: Playing cards

…depends on whether the order that the cards are drawn is significant or not…. I meant to say.

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Date: 9/03/2013 23:37:02
From: OCDC
ID: 277376
Subject: re: Playing cards

Ta. And no, the order doesn’t matter.

(Knew it was something simple, that I used to know.)

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Date: 9/03/2013 23:39:22
From: sibeen
ID: 277377
Subject: re: Playing cards

I, of course, have the only correct answer, as the question asked “to show workings”.

diddly gets half marks :)

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Date: 9/03/2013 23:40:47
From: diddly-squat
ID: 277378
Subject: re: Playing cards

OCDC said:


Ta. And no, the order doesn’t matter.

(Knew it was something simple, that I used to know.)

Combination —> order doesn’t matter
Permertation —> order does matter

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Date: 9/03/2013 23:40:51
From: diddly-squat
ID: 277379
Subject: re: Playing cards

OCDC said:


Ta. And no, the order doesn’t matter.

(Knew it was something simple, that I used to know.)

Combination —> order doesn’t matter
Permertation —> order does matter

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Date: 9/03/2013 23:41:31
From: diddly-squat
ID: 277380
Subject: re: Playing cards

sibeen said:


I, of course, have the only correct answer, as the question asked “to show workings”.

diddly gets half marks :)

Dude.. I showed how to work a calculator to get the answer…

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Date: 9/03/2013 23:42:21
From: OCDC
ID: 277381
Subject: re: Playing cards

diddly-squat said:


OCDC said:

Ta. And no, the order doesn’t matter.

(Knew it was something simple, that I used to know.)

Combination —> order doesn’t matter
Permertation —> order does matter

*permutation

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Date: 9/03/2013 23:42:34
From: esselte
ID: 277382
Subject: re: Playing cards

Diddly squat and sibeen agree with each other, and seem to know what they are talking about.

I, on the other hand, seem to have got everything wrong.

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Date: 9/03/2013 23:43:56
From: Angus Prune
ID: 277383
Subject: re: Playing cards

OCDC said:


Ta. And no, the order doesn’t matter.

(Knew it was something simple, that I used to know.)

I remember learning this stuff in yr 11. Too bad I don’t remember what any of it was…

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Date: 9/03/2013 23:44:09
From: sibeen
ID: 277384
Subject: re: Playing cards

>Dude.. I showed how to work a calculator to get the answer…

Yes, but I showed an equation that can easily be worked out without recourse to electronic calculating machines :)

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Date: 9/03/2013 23:44:46
From: OCDC
ID: 277385
Subject: re: Playing cards

Angus Prune said:


OCDC said:

Ta. And no, the order doesn’t matter.

(Knew it was something simple, that I used to know.)

I remember learning this stuff in yr 11. Too bad I don’t remember what any of it was…


I learnt it in year 8 and tutored it for goodness knows how many years after, which makes it even more embarrassing.

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Date: 9/03/2013 23:47:01
From: esselte
ID: 277387
Subject: re: Playing cards

diddly-squat said:

1 deck —> nCr 52 5 = 2,598,960
2 deck —> nCr 104 5 = 91,962,520

Just out of interest, what does 5^52 calculate? Anything? Or is it just a random assembly of numbers and operations with no significance to decks of cards and combinations of cards?

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Date: 9/03/2013 23:48:17
From: diddly-squat
ID: 277388
Subject: re: Playing cards

OCDC said:


Angus Prune said:

OCDC said:

Ta. And no, the order doesn’t matter.

(Knew it was something simple, that I used to know.)

I remember learning this stuff in yr 11. Too bad I don’t remember what any of it was…


I learnt it in year 8 and tutored it for goodness knows how many years after, which makes it even more embarrassing.

Yeah but that was like a million years ago

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Date: 9/03/2013 23:48:53
From: sibeen
ID: 277389
Subject: re: Playing cards

5^52 = 2.22*10^36

It just means 5 × 5 × 5 …with 52 fives.

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Date: 9/03/2013 23:50:24
From: diddly-squat
ID: 277390
Subject: re: Playing cards

esselte said:


diddly-squat said:

1 deck —> nCr 52 5 = 2,598,960
2 deck —> nCr 104 5 = 91,962,520

Just out of interest, what does 5^52 calculate? Anything? Or is it just a random assembly of numbers and operations with no significance to decks of cards and combinations of cards?

5^52 simply equals 5 × 5 × 5 × 5 …. 52 times over

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Date: 9/03/2013 23:52:13
From: diddly-squat
ID: 277391
Subject: re: Playing cards

5^52 = 2.22 × 10^36

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Date: 9/03/2013 23:53:09
From: esselte
ID: 277392
Subject: re: Playing cards

So no significance to the question? It’s not, like, the number of possible combinations in 5 decks of cards or anything like that?

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Date: 9/03/2013 23:53:39
From: sibeen
ID: 277393
Subject: re: Playing cards

Lucky you got that last one in. I was about to give you half marks again.

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Date: 9/03/2013 23:54:23
From: sibeen
ID: 277394
Subject: re: Playing cards

Nil, esselte.

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Date: 9/03/2013 23:56:02
From: diddly-squat
ID: 277395
Subject: re: Playing cards

sibeen said:


Lucky you got that last one in. I was about to give you half marks again.

diddly 1.5
sibeen 1

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Date: 9/03/2013 23:56:38
From: esselte
ID: 277396
Subject: re: Playing cards

sibeen said:


Nil, esselte.

Hah. My parents paid for a private school education for me. I guess the jokes on them :)

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Date: 9/03/2013 23:57:06
From: Wocky
ID: 277397
Subject: re: Playing cards

esselte said:


So no significance to the question? It’s not, like, the number of possible combinations in 5 decks of cards or anything like that?

If I had 52 decks of 5 cards, and drew one card from each, the number of possible hands would be 5^52.

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Date: 10/03/2013 00:00:36
From: esselte
ID: 277398
Subject: re: Playing cards

Aha. So My answer was actually correct, and it’s just that OCDC asked the wrong question.

I feel much better now. Thanks Wocky!

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Date: 10/03/2013 00:02:15
From: Wocky
ID: 277399
Subject: re: Playing cards

esselte said:


Aha. So My answer was actually correct, and it’s just that OCDC asked the wrong question.

I feel much better now. Thanks Wocky!

I aim to please (:

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Date: 10/03/2013 00:02:50
From: diddly-squat
ID: 277400
Subject: re: Playing cards

and the two deck answer only holds if you assume that all cards are unique, that is, there is a way to distinguish between the 5 hearts in one deck and the 5 hearts in the other.

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Date: 10/03/2013 00:12:15
From: sibeen
ID: 277401
Subject: re: Playing cards

Good point, diddly. I didn’t consider that.

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Date: 10/03/2013 00:22:52
From: Rule 303
ID: 277407
Subject: re: Playing cards

esselte said:

My parents paid for a private school education for me. I guess the jokes on them :)

Were apostrophes an optional extra, by any chance?

;-)

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Date: 10/03/2013 00:35:51
From: esselte
ID: 277414
Subject: re: Playing cards

Rule 303 said:


esselte said:
My parents paid for a private school education for me. I guess the jokes on them :)

Were apostrophes an optional extra, by any chance?

;-)

It was an Anglican school. We were too busy learning about God to be bothered by such minutiae.

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Date: 10/03/2013 14:48:30
From: PM 2Ring
ID: 277675
Subject: re: Playing cards

diddly-squat said:


and the two deck answer only holds if you assume that all cards are unique, that is, there is a way to distinguish between the 5 hearts in one deck and the 5 hearts in the other.

Indeed. And if we don’t care which deck a card comes from, the answer is much smaller:
52C5 + 4×52C4 + 3×52C3 = 3748160.

That’s 52C5 combinations with no duplicated cards,
plus 4×52C4 combinations with one duplicated card,
and 3×52C3 with two duplicated cards.

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Date: 10/03/2013 14:52:14
From: OCDC
ID: 277676
Subject: re: Playing cards

Ta.

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Date: 10/03/2013 15:01:15
From: PM 2Ring
ID: 277683
Subject: re: Playing cards

I just ran a little Python program to confirm my formula. It took 17 minutes to count all the combinations. (But I did check it before I posted using several smaller deck sizes).

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