## Probability Question

For the discussion of math. Duh.

Moderators: gmalivuk, Moderators General, Prelates

Gibson19
Posts: 2
Joined: Tue May 05, 2009 7:43 pm UTC

### Probability Question

Hey guys... I have a math final today and I've been studying but can't figure out this one probability question

The question is... How many different 5 card hands can be dealt from a deck that has only red cards?????

I've tried all sorts of techniques and never seem to get the right answer which is (65,780)

Its killing me cause its so simple but I can't figure it out

Many thanks...

GreedyAlgorithm
Posts: 286
Joined: Tue Aug 22, 2006 10:35 pm UTC
Contact:

### Re: Probability Question

Unconventional solution: Google "65780 cards", click on the link that talks about dealing cards from a deck, find the comment with the number you're interested in, see what the comment has to say.
GENERATION 1-i: The first time you see this, copy it into your sig on any forum. Square it, and then add i to the generation.

CueBall
Posts: 477
Joined: Sun Apr 26, 2009 6:50 pm UTC
Location: Somewhere with a gherkin in the middle.
Contact:

### Re: Probability Question

There are only 26 red cards. So, I think the answer is thus.

First, it can be one of 26. Then 25. then 24. etc.

so 26 x 25 x 24 x 23 x 22 which = 7893600.

That, divided by the number of ways those 5 cards can be arranged (120) will give your answer.
Spoiler:
Zohar wrote:Cueball is being generally hilarious today.
Sungura wrote:Cueball, I...I...
...
<3
Box Boy wrote:Now let us wait for the outcome of CueBall's fight to the death!

Gibson19
Posts: 2
Joined: Tue May 05, 2009 7:43 pm UTC

### Re: Probability Question

Thank you cueball!

It all makes so much sense now...

*Commences kicking myself*

CueBall
Posts: 477
Joined: Sun Apr 26, 2009 6:50 pm UTC
Location: Somewhere with a gherkin in the middle.
Contact:

### Re: Probability Question

Heh, no problem.
Spoiler:
Zohar wrote:Cueball is being generally hilarious today.
Sungura wrote:Cueball, I...I...
...
<3
Box Boy wrote:Now let us wait for the outcome of CueBall's fight to the death!

534n
Posts: 26
Joined: Thu Feb 19, 2009 1:50 pm UTC

### Re: Probability Question

Isn't this a combination question?

26C5=65780

Where Combination is

xCn=[X+(x-1)+(x-2)...+(x-{n-1})]/n

NathanielJ
Posts: 882
Joined: Sun Jan 13, 2008 9:04 pm UTC

### Re: Probability Question

534n wrote:Isn't this a combination question?

26C5=65780

Where Combination is

xCn=[X+(x-1)+(x-2)...+(x-{n-1})]/n

Yep, CueBall's answer basically goes through the derivation of what a combination is. Whichever method works for you.
Homepage: http://www.njohnston.ca
Conway's Game of Life: http://www.conwaylife.com

### Who is online

Users browsing this forum: No registered users and 7 guests