See “In the Cards.” Jack runs a card shop. Linda, who knows little or nothing about baseball or baseball cards, agreed to run the shop for Jack while he went out for dinner. Jack told Linda she could sell any card for the price marked on the card. Then he pointed to a case containing the more expensive cards and said that he might negotiate the price on those cards if customers would wait until he returned. 

Shortly after Jack left, Linda sold a small boy an Ernie Banks rookie card for $12. The card bore a price sticker that stated “1200.” The boy apparently was unaware of the card’s true value and did not try to negotiate its price. Did Linda have authority to sell the card for $12? Does Jack have any basis for suing her for his losses if the boy is able to keep the card?