John sends Carol an e-mail message stating that if Carol will promise to pay him $500,000, John will sell his vacation home in Big Bear to Carol. John’s e-mail message also says that if Carol wants to buy his vacation home, she must e-mail his sister and let her know that she wants to buy the home by December 1, because John will be out of the country on an African safari with no e-mail access. John’s e-mail message provides his sister’s e-mail address to Carol, but is not courtesy copied to his sister. Before John leaves on safari, he signs a power of attorney authorizing his sister to sell his vacation home in his absence.

On November 30, Carol replies to John’s e-mail stating that she wants to buy his vacation house. On December 6, John’s safari reaches a small town where John can telephone his sister. John asks his sister whether she has heard from Carol about buying the vacation home. His sister tells him that she has not heard from Carol. John instructs his sister to sell the vacation home to Bob. John explained to his sister that Bob was young, but had inherited a lot of money and previously said he wanted to buy the vacation home. John is anxious to sell the vacation home before the end of the year for income tax purposes. On December 18, on behalf of John, John’s sister enters into a written contract with Bob to sell the vacation home to Bob (assume that John’s sister has the authority to enter into a legally binding contract on John’s behalf).

Assuming that John’s offer to Carol and Carol’s acceptance of John’s offer are both legally sufficient, is there legally sufficient consideration to make John’s and Carol’s contract enforceable? Explain why or why not.