The host of a game show offers the guest a choice of three doors. Behind one is an expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

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

A man is trapped in a room. The room has only two possible exits doors. Through the first door there is a room constructed from magnifying glass. The blazing hot sun instantly fries anything or anyone that enters. Through the second door there is a fire-breathing dragon. How does the man escape?

Forwards I am heavy, backward I am not. What am I?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

Can you decipher these quotes by Albert Einstein?
Blf xzm mvevi hloev z kilyovn lm gsv ovevo lm dsrxs rg dzh xivzgvw.

How many Watermelons are there in the below picture?