OT - What we need around here is a good online puzzle...

QuikSand · 02-05-2004, 08:42 AM

We've had, from time to time, some fun working together (or competitively) on various puzzles and games online. I'm itchy for more of the same.

Anyone have any links to puzzles, games, or the like that might make for some good fodder for the crowd here?

cuervo72 · 02-05-2004, 08:46 AM

Quote:

Originally Posted by QuikSand

We've had, from time to time, some fun working together (or competitively) on various puzzles and games online. I'm itchy for more of the same.

Anyone have any links to puzzles, games, or the like that might make for some good fodder for the crowd here?

hxxp://www.flooble.com/perplexus/

QuikSand · 02-05-2004, 08:49 AM

Okay, the most recent unsolved puzzle from the flooble site is right here:

Quote:

Originally Posted by flooble

Two identical pack of cards A and B are shuffled throughly. One card is picked from A and shuffled with B. The top card from pack A is turned up.
If this is the Queen of Hearts, what are the chances that the top card in B will be the King of Hearts?

Airhog · 02-05-2004, 09:08 AM

1 in 52?

Probably not the right anwser, because that would be far to easy.

A coin could flip 100 times and land on heads but that doesnt mean the next flip is anything but 50-50

Nyarlahotep · 02-05-2004, 09:10 AM

I think you forgot about the card that got moved over.

QuikSand · 02-05-2004, 09:10 AM

Airhog, I think you're a letter off.

Huckleberry · 02-05-2004, 09:11 AM

.0192378838327784

QuikSand · 02-05-2004, 09:17 AM

Well, here's my solution.

We have two layers to this -- there's the case where the Kh was moved from deck A to deck B, and the case where some other card was. At first, this seems like a 1/52 vs 51/52 probability - but I don't think so. Since we know that the Qh was not moved, there are only 51 cards that could have been moved from A to B. So, I believe the chance that the card moved was the Kh is actually 1/51.

Then, we have to multiply each case by the associated conditional probability that the top card in deck A is Kh. That should be easy.

So, the model is this:

P(Kh moved) x P(Kh on top) = 1/51 * 2/53
plus
P(Kh didnt move) x P(Kh on top) = 50/51 * 1/53
equals
(2 + 50) / (51 x 53) = 52 / (51 x 53) = 52/2703.

edit: ugh. 50 * 1 = 50, not 51.

Airhog · 02-05-2004, 09:20 AM

okay once again I show how much of a dumbass i really am

Huckleberry · 02-05-2004, 09:31 AM

I got lazy. I just said 1/53 + (1/51)/53.

Franklinnoble · 02-05-2004, 11:45 AM

02-05-2004, 09:08 AM	#4
Airhog Captain Obvious Join Date: Aug 2001 Location: Norman, Oklahoma	1 in 52? Probably not the right anwser, because that would be far to easy. A coin could flip 100 times and land on heads but that doesnt mean the next flip is anything but 50-50 __________________ Thread Killer extraordinaire Yay! its football season once again!

02-05-2004, 09:11 AM	#7
Huckleberry College Starter Join Date: Dec 2001	.0192378838327784 __________________ The one thing all your failed relationships have in common is you. The Barking Carnival (Longhorn-centered sports blog) College Football Adjusted Stats and Ratings

02-05-2004, 09:17 AM	#8
QuikSand lolzcat Join Date: Oct 2000 Location: Annapolis, Md	Well, here's my solution. We have two layers to this -- there's the case where the Kh was moved from deck A to deck B, and the case where some other card was. At first, this seems like a 1/52 vs 51/52 probability - but I don't think so. Since we know that the Qh was not moved, there are only 51 cards that could have been moved from A to B. So, I believe the chance that the card moved was the Kh is actually 1/51. Then, we have to multiply each case by the associated conditional probability that the top card in deck A is Kh. That should be easy. So, the model is this: P(Kh moved) x P(Kh on top) = 1/51 * 2/53 plus P(Kh didnt move) x P(Kh on top) = 50/51 * 1/53 equals (2 + 50) / (51 x 53) = 52 / (51 x 53) = 52/2703. edit: ugh. 50 * 1 = 50, not 51. Last edited by QuikSand : 02-05-2004 at 10:16 AM.

02-05-2004, 09:20 AM	#9
Airhog Captain Obvious Join Date: Aug 2001 Location: Norman, Oklahoma	okay once again I show how much of a dumbass i really am __________________ Thread Killer extraordinaire Yay! its football season once again!

02-05-2004, 09:31 AM	#10
Huckleberry College Starter Join Date: Dec 2001	I got lazy. I just said 1/53 + (1/51)/53. __________________ The one thing all your failed relationships have in common is you. The Barking Carnival (Longhorn-centered sports blog) College Football Adjusted Stats and Ratings

02-05-2004, 09:10 AM	#5
Nyarlahotep College Benchwarmer Join Date: Mar 2003	I think you forgot about the card that got moved over.

02-05-2004, 11:45 AM	#11
Franklinnoble Banned Join Date: Jul 2002 Location: Placerville, CA	2/3

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)