Here is something interesting

[kate]

Three people have collected 30 $ for three rooms in hotel, they gave them on the reception, but when the manager came he decided to make them a discount - 5 $. He gave the money to the piccolo the give them back, but he decided to keep 2 of these 5 $ for himself, and to give back 1 $ to each of the three people. This way the people's rooms now cost 9 $ each. Well 3.9 = 27 + 2 (the piccolo's) = 29 $, where is the 1 $.