Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Why is the Hole below a Lock?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

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?

If eleven plus two equals one, what does nine plus five equal?

People put me on the table and cut me but do not eat me. What am I?

What is the word or phrase?

Which English verb becomes past tense just by rearranging the letters?

Can you make the number 24 by utilizing the numbers 1, 3, 4 and 6? You must use one number only one time and you can use mathematical operation symbols anytime anywhere.

Which point will the car reach to go out?