A wager on a horse race is very different than many other forms of gambling. Horse racing payoffs are calculated on a Pari-mutuel basis. Basically, this means that the house (the racetrack) does not care who wins a given race. The odds on each horse to win are determined by what proportion of the total money wagered is placed on that horse.
The racetrack handles the money, keeps a percentage or commission, and calculates the horses’ odds based on the public’s preferences. The remaining money is then paid back to the players who hold winning tickets.
Each wagering pool at Delaware Park has a specific take-out percentage, or commission rate, as illustrated below: