I am white when I am dirty, and black when I am clean. What am I?

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

What does below pictogram mean?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

What has one eye, but can’t see?

What part of the chicken has the most feathers?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

Prove that the below maths equation is true.

8 + 8 = 91

You are driving down the road in your car on a wild, stormy night, when you pass by a bus stop and you see three people waiting for the bus

An old lady looks as if she is about to die.
An old friend who once saved your life.
The perfect partner you have been dreaming about.
Knowing that there can only be one passenger in your car, whom would you choose?

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?