SOLUTION: Show that in a single throw of two dice, the probability of throwing more than 7 is equal to that of throwing less than 7, and hence find the probability of exactly 7.

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Question 1083228: Show that in a single throw of two dice, the probability of throwing more than 7 is equal to that of
throwing less than 7, and hence find the probability of exactly 7.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
sum of 2 has 1 way 1,1
sum of 3 has 2 ways 1,2 and 2,1
sum of 4 has 3 ways 1,3; 2,2;3,1
5 has 4 ways
6 has 5 ways
8 has 5 ways (symmetry)
9 has 4 ways
10 has 3 ways
11 has 2 ways
12 has 1 way
Those are 15/36 for each side with a sum of 30/36
That leaves a 6/36=1/6 probability for a sum of 7.