Racetracks quote the approximate odds against each horse winning on a large board called a tote board.The odds quoted on a tote board for a race with four horses are as follows.

Horse Number . . . . . . . . . . . . . . . . . . .  Odds

2 . . . . . . . . . . . . . . . . . . . . . . . . . . ..... . . .  15 : 1

3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..... .  15 : 1

4  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......1 : 1

5  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........3 : 1

Determine the probability of each horse winning the race.