A dodecahedral die has 12 sides and has been weighted so that the die is 3 times as likely to land on a prime number (2, 3, 5, 7, 11) as it is a non-prime number (1, 4, 6, 8, 9, 10, 12). (Make sure to note that 1 is not a prime number!)

a) Construct an appropriate probability model for the experiment of rolling this weighted dodecahedral die and recording the number which faces up. Show your work step by step.

b) Use your model in part (a) to find the probability of the event that the number is even or a prime (or both). Show your work step by step