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

I am an odd number. Take away a letter and I become even. What number am I?

How can you leave a room with two legs and return with six legs?

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

One absent-minded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he travelled on foot to his friend's place a few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock. How did he know?

A girl was standing near the window thinking something. All of a sudden she decides something and throws something out of the window. She dies very soon after throwing it. She was perfectly healthy and had no disease or allergy. No one killed her and she did not commit suicide.

Can you think of any possible explanation that is logical as well for what happened there?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

Can you complete the sequence?

192, 021, 222, 324, 252, 627, 2__, 9__?