What does this mathematical rebus means ?

Can you find the company name in the pictogram below?

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?

Solve the following series:
AZ, GT, MN, __, YB

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

Who always enjoys poor health?

Which fur should we be getting from the Lion?

Can you decipher the below rebus?

PBLUESAISNUERSES

Which is heavier: a ton of bricks or a ton of feathers?