SOLUTION: If you roll a pair of dice five times, find the probability of each outcome. -You get doubles exactly once. -You get exactly three sums of 7. -You get at least one sum of 7

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Question 1160749: If you roll a pair of dice five times, find the probability of each outcome.
-You get doubles exactly once.
-You get exactly three sums of 7.
-You get at least one sum of 7.
-You get at most one sum of 7.

Answer by ikleyn(52778) About Me  (Show Source):
You can put this solution on YOUR website!
.

            There are two totally different problems in this post.

            Therefore,  I will answer  (b),  (c)  and  (d)  ONLY   (since these three parts logically comprise one problem)


The probability to get the sum of 7 at each single roll a pair of dice is  1%2F6

     ( since there are 36 outcomes, in total, and only six are successful, 

     (1,6), (2,5), (3,4), (4,3), (5,2), and (6,1) ).


So the answers (and the solutions) are



(b)  P = C%5B5%5D%5E3%2A%281%2F6%29%5E3%2A%285%2F6%29%5E2 = 0.03215.


(c)  P = 1 - %285%2F6%29%5E5 = 0.598122.


(d)  P = %285%2F6%29%5E5 + C%5B5%5D%5E1%2A%281%2F6%29%2A%285%2F6%29%5E4 = 0.803755.