Which number should replace the question mark?

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

A person is found murdered in his Chamber. When the crime scene is investigated, the Investigator find out that there is a calendar on which the victim has written a few numbers with his blood. The numbers are 4, 11, 11 and 4.

There are four suspects in the murder, John, Jacob, Anna and Lee. Can you find out who is the murderer?

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

A boy was at a carnival and went to a booth where a man said to the boy, "If I write your exact weight on this piece of paper then you have to give me $50, but if I cannot, I will pay you $50." The boy looked around and saw no scale so he agrees, thinking no matter what the carny writes he'll just say he weighs more or less. In the end the boy ended up paying the man $50. How did the man win the bet?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

Can you name some countries which do not have the alphabet 'A' in them?

What is the next shape from answers A, B, C, and D figure?

What does it mean?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?