SOLUTION: What's the probability that a sum of 7 or 11 appears at least twice, if the a pair of fair dice are tossed 3 times.
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Question 163450: What's the probability that a sum of 7 or 11 appears at least twice, if the a pair of fair dice are tossed 3 times. Answer by edjones(8007) (Show Source):
You can put this solution on YOUR website! The probability of 11 on one roll is 2/36
The probability of 7 on one roll is 6/36
The probability of 7 or 11 on one roll is 8/36=2/9
(a+b)^3=a^3+3a^2b+3ab^2+b^3
Let a=2/9 and b=7/9
We are only interested in the 1st 2 terms:
(2/9)^3+3(2/9)^2(7/9)=.1262 answer.
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Ed
