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 November 14th, 2011, 11:19 AM #1 Newbie   Joined: Oct 2011 Posts: 12 Thanks: 0 probability dice If you roll two fair dice, one red and one green. Whatis the probability that you get a sum of 7 given that one die is an even number? Thank you. November 14th, 2011, 11:41 AM #2 Senior Member   Joined: Oct 2011 From: Belgium Posts: 522 Thanks: 0 Re: probability dice 6 possibilities for 7 with 1 die even 1 + 6 6 + 1 4 + 3 3 + 4 5 + 2 2 + 4 possibilities with at least 1 die even = 3*3+3*3+3*3 = 27 answer: 6/27 November 14th, 2011, 11:54 AM #3 Newbie   Joined: Oct 2011 Posts: 12 Thanks: 0 Re: probability dice sorry, I dont get it why possibilities with at least 1 die even = 3*3+3*3+3*3 = 27? November 14th, 2011, 12:07 PM   #4
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Re: probability dice

Quote:
 Originally Posted by mathproblems sorry, I dont get it why possibilities with at least 1 die even = 3*3+3*3+3*3 = 27?
first die even, second die uneven: 3*3
second die even, first die uneven: 3*3
first die even, second die even: 3*3 November 14th, 2011, 12:12 PM #5 Newbie   Joined: Oct 2011 Posts: 12 Thanks: 0 Re: probability dice sorry, can did you get 3? November 14th, 2011, 12:30 PM   #6
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Re: probability dice

Quote:
 Originally Posted by mathproblems sorry, can did you get 3?
because there are 3 even and 3 uneven values on a die November 15th, 2011, 06:58 AM   #7
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Re: probability dice

Hello, mathproblems!

Quote:
 You roll two fair dice, one red and one green. What is the probability that you get a sum of 7, given that one die is an even number?

1,\,6),\ 2,\,5),\ 3,\,4),\ 4,\,3),\ 5,\,2) ,\ 6,\,1)" /> November 15th, 2011, 07:38 AM #8 Math Team   Joined: Apr 2010 Posts: 2,780 Thanks: 361 Re: probability dice If you are given that one die is even, it means that precisely one die is even right? Meaning the other is odd. 18 possibilities to have precisely 1 even. So a 1/3 chance that it'll give a 7. November 15th, 2011, 07:40 AM #9 Newbie   Joined: Oct 2011 Posts: 12 Thanks: 0 Re: probability dice thank you. sounds great November 16th, 2011, 10:08 PM #10 Newbie   Joined: Oct 2011 From: Jaipur Posts: 17 Thanks: 0 Re: probability dice Specific Multiplication Rule Only valid for independent events P(A and B) = P(A) * P(B) Example 3: P(A) = 0.20, P(B) = 0.70, A and B are independent. B B' Marginal A 0.14 0.06 0.20 A' 0.56 0.24 0.80 Marginal 0.70 0.30 1.00 The 0.14 is because the probability of A and B is the probability of A times the probability of B or 0.20 * 0.70 = 0.14. Dependent Events If the occurrence of one event does affect the probability of the other occurring, then the events are dependent. Conditional Probability The probability of event B occurring that event A has already occurred is read "the probability of B given A" and is written: P(B|A) General Multiplication Rule Always works. P(A and B) = P(A) * P(B|A) Tags dice, probability Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Threads Thread Thread Starter Forum Replies Last Post marko.games Advanced Statistics 2 November 12th, 2013 01:18 PM panky Probability and Statistics 2 December 13th, 2012 10:52 AM panky Probability and Statistics 1 November 11th, 2012 03:33 AM aaron-math Probability and Statistics 1 September 10th, 2012 10:09 AM Brimstone Algebra 10 May 30th, 2008 07:36 PM

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