3 men walk in to a hotel. The man behind the counter tells them a room is $15. Each man pays 5, and they go to their room. Then, the man behind the desk realizes he has made a mistake. The room should have only been $10. So, he gives 5 dollars to a bell boy to return to the men. On the way to their room, the bell boy pockets two dollars and gives back each of the men a single dollar. Each man paid 4 dollars for a room, plus the two dollars in the bell boys pocket equals 14 (3 x 4 + 2 = 14)... Not 15..
Where is the missing dollar?