How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

Can it be possible to build a house that has all its four walls facing towards the South?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

The captain of a ship was telling this interesting story: "We travelled the sea far and wide. At one time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly." How can that be possible?

Replace the question mark with the correct number below.

Why do we preferably have round manhole covers and not square ones?

Solve below popular number sequence
314 159 265 358 979 323 846 ?

What number do you get when you multiply all of the numbers on a telephone's number pad?

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for 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 ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?