Question

Two 6-sided dice are rolled. Find the odds of rolling s sum that is a prime number

Answer 1

Possible prime sums are 2,3,5,7, and 11
number of ways to get 2 = 1
numbr of ways to get 3 = 2
number of ways to get 5 = 4
number of ways to get 7 = 6
number of ways to get 11 = 2
total = 15

prob of that happening = 15/36 = 5/12
so prob of that NOT happening = 1-5/12 = 7/12

odds in favour of a sum which is prime = (5/12) : (7/12)
= 5 : 7