Sindy Birthday

Ten days ago Sindy was 7 years old. Next year she will turn 10.

How can this be?

Ah! Click here to read the solution.

The Hotel With 12 Rooms

13 people came into a hotel with 12 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the thirteenth guest to wait a little with the first guest in room number 1. So in the first room there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, …, and the twelfth guest to room number 11. Then he returned to room number 1 and took the thirteenth guest to room number 12, still vacant.

How can everybody have his own room?

Ah! Click here to read the solution.