Dunno where this came from, but it's quite fun.
Three men go into a hotel looking for a room for the night. The receptionist tells them that the rate is £30. They pay £10 each, and are given the key.
A while later, the receptionist realises he should have only charged them £25. So he gives the bellboy £5 to refund to the men.
The bellboy can't work out how to divide the £5 between the three men. So he refunds them £1 each and keeps £2.
So the men each paid £9 for the room - total £27 - and the bellboy kept £2 - taking the total to £29.
What happened to the other £1?
Try and work it out before reading the comment.