Why do you find that most of the buildings are deprived of the 13th floor?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

How many sides does a circle have?

This is a picture puzzle. You have to guess the name of the movie that can be related to the picture.

If an electric train is travelling south, then which way is the smoke going?

If two's company, and three's a crowd, then whats four and five ?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

10+10 and 11+11 can give you the same answer.

Explain how?

A dead body is found outside a multi-story multinational company. The case is reported and a homicide detective is called on the crime scene.

He looks at the body and then towards the building. From the position of the body, it is evident that the victim committed suicide. He goes to the first floor of the building and then walks in the direction of the dead body, opens the window and toss a coin in the air.

He goes to second floor and again repeats the process. He keeps doing this till he is done on all the floors. Then he returns back to the floor and tells his team that it is a murder.

How in heaven did he deduce that?

As we know that white starts the game of chess. Can you find the scenario shown in the picture below is possible when all the white pieces are at the original place while the black pawn is not as in the below picture?