Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Suppose you are sitting in an interview and the interviewee asks you an aptitude question.

You have three buckets with a capacity of 4 litres, 8 litres and 10 litres and you have a large tank of water. Now you have to measure 3 litres of water precisely using those buckets. How will you do it?

Move four matchsticks to the below square to form three squares?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

Give it food and it will live; give it water and it will die.

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?

There's a day, that comes around once a year.
To celebrate the man, you hold dear.
He gave you life, love and will pick you up if you fall.
When it comes to guys like him, He's the best of all.
Who is he?

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 ?

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