1. Let a: rolling an even number, b: rolling an odd prime number
2. a={2, 4, 6, 8, 10, 12, 14, 16}, b={3, 5, 7, 11, 13}
3. So n(a)=8, n(b)=5 , n(Sample Space)=n(S)=16
4. Since a and b are mutually exclusive events, that means they have no common elements, P(a or b)=P(a)+P(b)=