I have to submit a law school contract essay - Here is the fact pattern

Norse writes a letter to Odin on December 1^st and offers to sell him his motorcycle for $3000 if Odin accepts the offer by January 1^st. On December 15^th, Odin writes a letter to Norse that states, "How about $2500?" On December 16 Norse writes a letter to Odin, stating, "That number won't work for me. My offer is what I stated in my December 1^st letter." On December 18 Odin replies by letter, "Okay then. I accept your offer."

Norse then refused to sell the motorcycle to Odin.Does Odin have an enforceable contract with Norse?