Please Please help. I am struggling with this equation.
In horse​ racing, a trifecta is a race in which you must pick the​ first-, second-, and​ third-place winners in their proper order to win a payoff. If horses are​ racing, and you randomly select three as your bet in the​ trifecta, what is the probability that you will​ win? (Assume that all horses have the same chance to​ win.)