1. Sara found an old painting in her parents attic. She sold it at a yard sale to Carrie. Both Sara (the seller) and Carrie (the buyer) thought the painting was worth $400. Later, Sara found out it was an original design and worth $10,000. She would like to get her painting back from Sara! Does this describe a mutual or unilateral mistake, or neither? If it is a mistake, what can happen here? Can Sara get her painting back?