Which Tire

Someone wrote:

On a beautiful fall day, four of my granddaughter's friends decided to go for a drive instead of showing up to class on time. When they did arrive, the girls explained to the teacher they had had a flat tire. The teacher accepted the excuse, much to the girls' relief.

"Since you missed this morning's quiz, you must take it now," she said. "Please sit in the four corner seats in this room without talking." When they were seated, the teacher said, "On your paper write the answer to one question: 'Which tire was flat?'"

Those poor young ladies discovered what Abraham Lincoln already knew: No one has a good enough memory to lie.