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

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

The person who makes it has no need for it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?

In a competitive exam, each correct answer could win you 10 points and each wrong answer could lose you 5 points. You sat in the exam and answered all the 20 questions, which were given in the exam.
When you checked the result, you scored 125 marks on the test.

Can you calculate how many answers given by you were wrong?

What is the next number in the series?

15 29 56 108 208 ?

A Child was born in Lahore, Pakistan.

Still child is not a Pakistani citizen.why ?

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

Yesterday I fell from 30 feet high ladder but I don't get hurt. Why?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

Why is 6 afraid of 7?