Two Plus Two Older Archives

Two Plus Two Older Archives (http://archives2.twoplustwo.com/index.php)
-   Probability (http://archives2.twoplustwo.com/forumdisplay.php?f=23)
-   -   Inclusion - exclusion. Specific example (http://archives2.twoplustwo.com/showthread.php?t=307560)

08-04-2005 10:39 AM

Inclusion - exclusion. Specific example
 
Hi all,

My question is very specific and concerning an archived thread with BruceZ in the drivers seat:
http://archiveserver.twoplustwo.com/...art=1&vc=1

In Brucez's answer it follows:
" C(8,2)* 78/C(52,2) * 73/C(50,2) = 9.8%. C(8,2) is the number of ways to pick the 2 players. There are 73 pairs remaining after the first player chooses a pair"

- Now, why are there 73 pairs left after 1st player chooses a pair? I know we can't just pick from 12 ranks and pretend that the 2nd player can't pick a pair of the same rank as the first. But why 73...?

I want of course to be able to make the next term myself.

ty.

LetYouDown 08-04-2005 10:43 AM

Re: Inclusion - exclusion. Specific example
 
Because there are 12 ranks remaining where there are 6 ways to choose a pocket pair...C(4,2), and one rank remaining where there's only one way to choose the pair (only two cards left). C(12,1) * C(4,2) + C(2,2) = 73.

08-04-2005 10:59 AM

Re: Inclusion - exclusion. Specific example
 
Ahhh. of course.

thanks


All times are GMT -4. The time now is 06:45 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.