December 26th, 2006, 11:51 AM  #1 
Newbie Joined: Dec 2006 Posts: 28 Thanks: 0  Cards
If a card has drawn from a regular 52 card deck, what is the chance that the card will be either a 2 or a heart , or the 2 of hearts.

December 26th, 2006, 01:53 PM  #2 
Senior Member Joined: Dec 2006 Posts: 1,111 Thanks: 0 
I'd say that it's 1/13 + 1/4  1/52= 16/52 because the probability of choose a two is 1/13, and the probability of choosing a heart is 1/4, and the probability of finding the two of hearts must be subtracted, since it's included in both probabilities at once, but should only be included in one. In other words, find all the hearts and then all the twos that aren't also hearts, add them up and divide by 52. 
December 26th, 2006, 03:15 PM  #3 
Senior Member Joined: Nov 2006 From: I'm a figment of my own imagination :? Posts: 848 Thanks: 0 
What, infinity, don't you know how to reduce fractions? :P Anyway, the reduced answer is 4/13. 
December 26th, 2006, 04:33 PM  #4  
Senior Member Joined: Dec 2006 Posts: 1,111 Thanks: 0  Quote:
 
December 26th, 2006, 06:08 PM  #5 
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms 
Counting: A♥, 2♥, 3♥, 4♥, 5♥, 6♥, 7♥, 8♥, 9♥, 10♥, J♥, Q♥, K♥, 2♠, 2♣, 2♦ = 16 16/52 = 8/26 = 4/13. Figuring: 13 hearts + 4 2s  2♥ (otherwise counted twice) = 13+41 = 16 16/52 = 8/26 = 4/13. Fractions: 1/4 + 1/13  1/4 * 1/13 = 4/13 
December 27th, 2006, 08:14 AM  #6  
Senior Member Joined: Nov 2006 From: I'm a figment of my own imagination :? Posts: 848 Thanks: 0  Quote:
 
December 27th, 2006, 10:21 AM  #7  
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Quote:
 
December 30th, 2006, 01:10 PM  #8 
Senior Member Joined: Dec 2006 Posts: 1,111 Thanks: 0 
I just split off the last post and made it a new topic.


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