VB algorithm for coming up with a winner

I have a app im making that will predict the outcome of a TWO MAN race. Lets say there is 10 different racers , each have won and lost many times to each other .

i need help figuring out how to get vb to do the math to figure out based on previous races who will have the highest percentage chance of winning in the two man race

i have a form with a drop down with 5 racers in each drop down and a Race button i want to hit race and then get the odds on which racer will win by looking at past races and the opponents last ten race outcomes

i have the racers records in a different text file for each racer

any help would be great been racking my brain

I think you would need to provide more info what kind of info do you have stored in the race outcomes, how many races have they ran, how many against each other. The most important stats would be avg race time and head to head meetings between the 2.