Why is Saturday stronger than Monday?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

You know three triplets: Frank John and Wayne (need to return your money). Frank always tells the truth while John and Wayne always lie. You meet one of them on the road and can ask him a three-word question.
Which question, will you ask?

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?

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

What do you answer even though it never asks you questions?

What is the riddle which can be asked all day with a different correct answer each time.

There was a strange boy who was born before his father. How can this be possible?

Who has married many women but was never married?