total = 6² = 36 eventos

a) soma = 8

{(2,6), (3,5), (4,4), (5,3), (6,2)}; 5 eventos

prob = 5/36

b) soma > 8

{(3,6), (4,5), (4,6), (5,4), (5,5), (5,6), (6,3), (6,4), (6,5), (6,6)}; 10 eventos

prob = 10/36 = 5/18