Before Mount Everest was discovered, what was the highest mountain in the world?

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?

What is the word or phrase below?
R | E | A | D

When is the top of a mountain similar to a savings account?

On a magical land of Mexico , all the animal in the land are rational.

There are 10 tigers and one goat.
Tiger can eat goat but since it's a magical land , the tiger who eats the goat , turns into goat and then can be eaten by the remaining tiger(s).

If we leave them for some time then how many goat and tiger will be there , when we come back ?

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

There was a blind man. He had four socks in his drawer either black or white. He opened it and took out two socks. Now the probability that it was a pair of white socks is 1/2.

Can you find out the probability that he had taken out a pair of black socks ?

Keyboard words are not in alphabetical order, Why?

If eleven plus two equals one, what does nine plus five equal?

What can you hold in your right hand, but never in your left hand?