Old puzzle but a good one...........
Three friends share a meal at a restaurant.
The bill comes to £30
They divide it equally, paying ten pounds each.
But the waiter realises he's made a mistake and should have charged £25.
He gives the friends five pounds back .
They decide to take one pound each and give the waiter a £2 tip
So, each person ends up paying £9 and the waiter keeps £2, making £29 in total.
What happened to the missing £1?