We know, we know: Lawyers ain't math majors.
But this requires only arithmetic, for heaven's sake:
Three men were on a business trip and had to stay in a hotel over night. The price of the room was $30.00, so the men decided to split one room, three ways. Each one paid $10.00. Well after they paid, the manager realized that he overcharged them on their room. The room only cost $25.00, so he gave the bellboy five one dollar bills to give to the three men. On his way up to the room the bell boy was trying to think of a way to split $5.00 three ways. After thinking about it awhile, he decided to keep $2.00 for himself and give each man $1.00 back. Now, if each man (who paid $10) gets $1 back that means they each paid $9.00 ($10 - $1 = $9 ). $9.00 multiplied by 3 (because there are three men) equals $27.00 plus the $2.00 the bell boy kept equals$29.00! What happened to the missing dollar?
Good luck! (And don't fritter away the whole day thinking about it.)
(H/T to Professor Steve Miller of Williams College.)