What is so fragile that saying its name breaks it?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

How many words can a pen with half refill write?

Your job is to measure 45 minutes if you have only two cords and matches to light the cords.

1. The two cords are twisted from various materials, so their different segments can burn at different rates.
2. Each cord burns from end to end in exactly one hour.

Describe your way of measuring the 45 minutes.

I am never scared but became petrified and can’t live in a house but would die to make one. What am I?

Can you solve the maths in the below-given picture equation?

How can a man go eight days without sleep?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

John was piloting a plane behind a car but was never able to overtake it. Why?

A woman lives in a skyscraper thirty-six floors high and is 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?