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October 17th, 2013, 11:40 PM  #1 
Senior Member Joined: Sep 2011 Posts: 102 Thanks: 1  Probability
Hi, i need help for the below qns. thanks. Three unbiased dice are thrown . Find the probability that (i) they all show different numbers ii). at least two shows the same number. 
October 18th, 2013, 02:04 AM  #2 
Math Team Joined: Apr 2010 Posts: 2,780 Thanks: 361  Re: Probability
(i) For the first die, how many values can you get? For the second die, how many values can you get, given the value of the first die? For the third die, how many values can you get, given the value of the first and second dice? (ii) How is this probability related to the probability found in question (i)? 
October 18th, 2013, 02:12 AM  #3 
Senior Member Joined: Sep 2011 Posts: 102 Thanks: 1  Re: Probability
i). 6/6*5/6*4/6= 5/9 ii). 1 5/9 = 4/9 Am i correct? 
October 18th, 2013, 04:56 AM  #4 
Senior Member Joined: Jun 2013 From: London, England Posts: 1,316 Thanks: 116  Re: Probability
Yes, that's correct. You could also work out: iii) The probability that all three are the same. iv) The probability that two are the same and one is different. That gives you a complete picture of all the possible outcomes. 

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