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Old 07-27-2007   #3
raja
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Sample space is 6^10,Odds of getting seven are: 1/6Odds of NOT getting a seven are: 5/6The number of ways you can hit a 7 or 11 is (1, 6), (2, 5), (3, 4), (4, 3), (5, 2), (6, 1), (5, 6), and (6, 5). So the probability of hitting would be 8/36 or 2/9.So the probability of hitting this exactly 5 times in 10 rolls would be C(10, 5) * (p)^5 (1-p)^5, where C(10, 5) is "10 choose 5", and p = 2/9. Evaluating this we get 252*[(2/9)^5](7/9)^5] = 0.03887.