On June 25, Sam Seller mailed Ben Buyer an offer to sell his car to Ben for $10,000. The offer arrived on June 28. Ben put his acceptance in the mail on June 30, but, because of the long holiday, it did not arrive at Sam's home until July 7. Sam found a buyer who was willing to pay $11,000 for the car and mailed a revocation on June 27. Ben got the revocation on July 1. Was a contract formed between Sam and Ben? If so, on what date did it become effective?
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