Before Mount Everest was discovered, what was the highest mountain in the world?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

I am a three digit number.
My tens digit is five more than my ones digit.
My hundreds digit is eight less than my tens digit.
What number am I?

A man is looking at a photograph of someone. His friend asks who it is. The man replies, “Brothers and sisters, I have none. But that man’s father is my father’s son.” Who was in the photograph?

Five thieves looted a bank and they ran away in a car. The bank staff informed the police and they began the search of their car in their jeep. They found them on a road and chased them eventually catching them. The light that is used to fill the number plate was broken on the thieves' car. Also, the headlights of the jeep police were not working. How were the police able to catch the thieves then?

Can you find the missing piece of the Porsche?

What has many teeth, but cannot bite?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?