A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

Replace the question mark with the correct number in below Picture:

I have branches, but no fruit, trunk or leaves. What am I?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

Can you find the hidden animal in the picture below?

Why 1729 is a magic number? Answer Logically.

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

What Adam and Eve do not have but the rest of the people have?