Three people go to a hotel. The guy at the desk says the room is $30.00
So each of them pay $10.00 and go to their room.
A while later the guy at the desk realises that the room is only $25.00 so he sends the bellboy to their room with the $5 difference.
On the way the bellboy couldn't figure out how to split the $5 evenly between the 3 of them so he gives $1 to each of them and keeps $2 for himself.
So - The three people each paid $9 for the room which is a total of $27. Add the $2 that the bellboy kept and you have a total of $29.
Where's the other $1 ?!?!?!