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?

I am a ten letters word
The first four letters have the power to rule,
Next, four-letter can be eaten.
The next three-letter represents a lady.
I can fly as well

what am I looking for?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

What goes up but never comes down?

A man was just doing his job when his suit was torn. Why did he die three minutes later?

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

Explain how?

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

Can it be possible to build a house that has all its four walls facing towards the South?

If 21x = 79x, what is the value of x?