On July 1^st, Rawan, a merchant, wrote to Tara: "I offer to sell you a 60-inch 4K LED television for $500. This is a firm offer for 60 days from today's date. (Signed) Rawan."

On July 10^th, Tara received a letter from Rawan: "I hereby revoke my offer of July 1^st."

On August 15^th, Tara wrote and mailed a letter to Rawan: "I accept your offer of July 1^st."

1. Is there a contract? If no, explain why not. If yes, explain why, including when the contract became effective.

1. Now assume that that Rawan's offer stated that it was firm offer for five months, and that on October 15th, Tara received a letter from Rawan, dated October 10th^th: "I hereby revoke my offer of July 1^st." On November 15^th, Tara mailed an acceptance.

Is there a contract? Explain.