we can get 5 in 4 diff. ways: (2,3) (3,2) (1,4) (4,1)
similarly 8 in 5 diff ways: (3,5) (5,3) (4,4) (6,2) (2,6)
now neglecting all other outcomes we are concerned with getting either 5 or 8 right?
so P(5 before 8) =4/(4+5) = 4/9
similarly P(8 before 5)=5/9