Carlos responded to an advertisement placed by Dawn, a doctor, seeking a physician's assistant. After an interview, Dawn offered Carlos the job and said she would either pay him $$100,000$ per year; or pay him $$80,000$ per year and agree to convey to him a house $($needing quite a bit of work done on it$),$ worth about $$75,000,$ if he would agree to work for her for four consecutive years.

Carlos accepted the offer and said, $"$I$\text{'}$d like to go with the second option, but I would like a commitment for an additional three years after the first four." Dawn said, "Okay then, l$\text{'}$d like you to start next week."

After Carlos started work, Dawn delivered a letter by mail, post$-$marked on the day of their initial job discussion after Carlos had started. She signed the letter. It stated that he had agreed to work as a physician's assistant at a salary of $$100,000$ per year.

After Carlos had worked for three years and nine months, Dawn decided that she would sell the house to her sister, not Carlos. She likes Carlos'