help

Mahowny rolls two fair, six-sided dice. You don't know what the rolls were, but you are told that the sum of the two rolls is a prime. What is the probability that the sum of the two rolls is 7?

prime number rolls

1,1   added after guest pointed out my error of omision    1

1,2    2,1                                              2

1,4    4,1    23,  32,                              4

1,6     2,5    3,4   doubled                     6

5,6   6,5                                               2

Total                                                   15     edited

probability is     6/15    

Thanks for picking up my error guest :)

The sample space is 6^2 =36

The probability of rolling a prime number is 15 / 6^2 =5 / 12

The probability of a rolling a sum of 7 is 6 / 36 = 1 / 6