2. Beachcomer, a coin dealer, sues to rescind a purchase by Boskett, who paid $50 for a dime both parties thought was minted in San Francisco. In fact, it was a very valuable dime minted in Denver. Beachcomer asserts a mutual mistake of fact regarding the genuineness of the coin as San Francisco-minted. Boskett contends that the mistake was as to value only. Explain who should win.