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

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

Living above a star, I do not burn
Eleven friends and they do not turn
I can just be visited in a sequence, not once or repeatedly
PQRS are my initials
Can you tell my name accurately?

Can you find out which options fits best with the missing column?

Thirty friends were on a hiking trip when they decided to enjoy the bonfire. They assembled for it and agreed to play a game. For that, they divided themselves into five teams with seven members each, forming five rows.

How did they manage to achieve this formation?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

A woman lives in a Tall building thirty-six floors high and served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?

How old is your son? asked a man to his neighbour. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.

How old is the man's son ?

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

What has lots of eyes, but can’t see?