On May 12, Leonard offered to sell Ginrich, an acquaintance, a used washer-dryer for $400. Leonard told Ginrich that he had until May 17 to accept this offer. On May 13, Leonard received an offer to purchase the washer-dryer for $450 from Bolton, a friend. Leonard immediately accepted Bolton’s offer. On May 14, Bolton saw Ginrich and mentioned that he (Bolton) had just purchased a washer-dryer from Leonard. On May 15, however, Ginrich notified Leonard that he accepted the offer to buy the washer-dryer for $400. Was Ginrich’s acceptance valid?