What if kristy and judy were visiting face-to-face and kristy made the offer to sell her property to judy and dave overheard and chimed in "i'll buy it!" before judy could reply. does dave have a contract?

Based on the scenario, Dave isn't considered to have a contract unless the person accepted him to be one of the people to be given by the offer as acceptance could be given if the person offered it to the person whom she or he wants to have the contract with.