it's not all that sophisticated but it has given a hard time even to some math people. 3 people on a trip go to a hotel to get a room to spend the night in. the desk clerk just happens to not be there, so the bellhop says can take care of you but i'm not sure how much a room cost, i think it's $30. so they pay him $30.....$10 each. the desk clerk comes back and the bellhop tells him what happened. he tell the bellhop he overcharged the people. he gives the bellhop $5 and tells him to go to their room and return the money. on the way to the room the bellhop figures they'll never know, so he decides to keep $2 for himself and only give them back $3. so he gets to their room, tells them what happened and gives them back $3, so each person gets $1 back, making each person's final cost $9. so 3 x $9 = $27, plus the $2 the bellhop kept is $29. what happened to the other dollar?