The Lost Pound!

Puzzle number 141.

Three friends check into a hotel for the night and the receptionist tells them the bill is £30, payable in advance. So, they each pay the receptionist £10 and go to their room.

A few minutes later, the receptionist realises she has made an error and overcharged the group by £5. She asks the doorman to return £5 to the 3 friends who had just checked in.

The doorman sees this as an opportunity to make $2 as he reasons that the three friends would have a tough time dividing £5 evenly among them; so he decides to tell them that the receptionist made a mistake of only £3, giving a pound back to each of the friends. He then pockets the leftover £2 and goes home for the day!

Now, each of the three friends gets a pound back, thus they each paid £9 for the room which is a total of £27 for the night. We know the bellhop pocketed £2 and adding that to the £27, you get £29, not £30 which was originally spent.

Where did the other pound go?