1. The problem statement, all variables and given/known data Two tetrahedral dice (four-sided dice) are thrown. What is the probability that the sum of the scores is: a) even b) prime c) even or prime? 2. Relevant equations 3. The attempt at a solution a) P(even) = 1/2 b) P(prime) = 9/16 c) c for confused Can someone please explain the theory behind answering Question c? Cheers.