Riddle: Where did the dollar go?
Three friends went to a hotel and paid 30 dollars for a room (10 dollars each). Later, the administrator remembered that the room only costs 25 dollars and sent 5 dollars to the maid to return to the friends.
But the maid decided that splitting the 5 dollars among three was inconvenient, so she returned 1 dollar to each friend and kept 2 dollars for herself.
Now, each friend paid 9 dollars (a total of 27 dollars), and there are 2 dollars with the maid.
27 + 2 = 29. Where did the 1 dollar go?