Generally, in situations such as this where one person enters into a competition with a company or corporation with an explicitly defined prize, this constitutes a unilateral contract. Unilateral contracts are defined by the offering of a reward for a specifically defined act, and this contract is accepted when the contractee completes the act. In this case, Rocky Mountain Races, Inc., and Monica did have a uniform contract. Furthermore, because Monica entered the race and was declared the winner, she fulfilled her end of the contract thus accepting the contract (and qualifying for the reward from the contractor). However, because Rocky Mountain Races, Inc., included a provision that they could change the terms of the race at any time, Monica isn't entitled to the $10,000 reward, she is entitled to whatever reward Rocky sees fit.
