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MATH HELP

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Yung_Gnarley
Posts: 9093 - Karma: 3,041
If you draw 9 cards from a standard deck, what is the probability of drawing a "2 of a kind"?

please help please
Oct 29 2010 1:38AM
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BootySpunk.
Posts: 8148 - Karma: 84
Dude I will help you!
Oct 29 2010 1:39AM
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Schlop
Posts: 3640 - Karma: 24
52 cards:
13 numbers/faces x 4 suites



there's a headstart
Oct 29 2010 1:40AM
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Yung_Gnarley
Posts: 9093 - Karma: 3,041
I need more help
Oct 29 2010 1:43AM
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1337
Posts: 31061 - Karma: 29,366
I thought I knew how to do this then realized I could not.

Time to go back to school :\
Oct 29 2010 1:48AM
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tuna.
Posts: 2627 - Karma: 111
i got you buddy!

52p1 because your choosing 1 card from a deck first and order matters so the formula for that would be 52!/52-1! which is just 51.

so you take 51 and multiply that by 3p1 because you've already chosen one card, and theres 4 of each card, so 3 left, and your choosing one more. so it should be 3!/3-1! which is just 2! which is just 2. so i think its just 51x2, but im not positive whether or not you use permutations or combinations. but if i remember right, since your only chosing one card at a time, it doesnt matter.

hope that helps
Oct 29 2010 1:48AM
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skichicky3
Posts: 2593 - Karma: 64
is it drawing two with replacement or without, thats pretty important
Oct 29 2010 1:48AM
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Yung_Gnarley
Posts: 9093 - Karma: 3,041
haha yes! thanks dude!
Oct 29 2010 1:49AM
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Yung_Gnarley
Posts: 9093 - Karma: 3,041
well you're drawing all 9 at once
Oct 29 2010 1:49AM
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tuna.
Posts: 2627 - Karma: 111
no problem, i think i fucked that first part up though, should be 52, not 51. sorry if all the details arent perfect, just trying to get you started.
Oct 29 2010 1:50AM
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tuna.
Posts: 2627 - Karma: 111
and i definitely didnt see that your only drawing 9 cards, disregard my response for the most part.
i wish i could say i was high.
Oct 29 2010 1:51AM
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Yung_Gnarley
Posts: 9093 - Karma: 3,041
need more help
Oct 29 2010 2:20AM
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Bungholio
Posts: 973 - Karma: 5
i will attaampt a tripple tomorrow guyz
Oct 29 2010 2:20AM
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Gameboy
Posts: 2657 - Karma: 127
I totally did this exam today, BUT, I don't know if it went well. So here's my help

In order to achieve your statement, you need to obtain two success out of 9. so it's 9 nCr 2 (you're suppose to have that on your calculator)

Take this result and multiply it by the probability of that success which is (0,25)^2. You need to add ''^2'' cause you need 2 success.

Then multiply this result by the probability of a failure (0,75)^9-2 so, (0,75)^7 cause you'll have 7 failures.

It follows the ''binomial'' (I don't know how it's called in English)

Something like this : X (wave sign) B (n:p)

If you have any questions, reply, I'll take a look later.
Oct 29 2010 2:25AM
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Yung_Gnarley
Posts: 9093 - Karma: 3,041
i'll try that
Oct 29 2010 2:26AM
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Gameboy
Posts: 2657 - Karma: 127
Give me news!
Oct 29 2010 2:27AM
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McFellon
Posts: 1841 - Karma: 2,005
ask jay-z
Oct 29 2010 9:26AM
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