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

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

One night, a man runs away from home. He turns left and keeps running. After some time he turns left again and keeps running. Later, he turns left one more time and runs back home—but when he gets home, he finds a man in a mask. Who was the man in the mask?

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

What do you see in the given picture?

I always drive my customer away.

Who am I?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

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?