Count the number of squares in the picture below.

You are in a land where thirty men and two women were dressed in classic black and white dresses.
They begin to fight as soon as any of them move.

Where are you?

I am a five-letter word and comprises two different vowels and three same consonants. I am so strong that I can spoil your entire work.

Can you find out who am I?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

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 the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

What does below pictogram mean?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

What has many keys but can’t open a single lock?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?