What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Can you identify the direction in which this bus is moving; left or right?

Hint: The bus is moving on the roads of London.

Prove that twice of ten is the same as twice of eleven.

If your uncle’s sister is not your aunt, what relation is she to you?

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

Three people enter a room and have a green or blue hat placed on their heads. They cannot see their own hat but can see the other hats.
The colour of each hat is purely random. They could all be green, blue, or any combination of green and blue.
They need to guess their own hat colour by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $10,000 each, but if anyone guesses incorrectly they all get nothing.
What is the best strategy?

A police officer was passing by when he saw a guy hiding. He walked up to him and genially asked, "What is your name?"

"Shut up!" the boy responded.

"Where are your manners?" asked the outraged police officer.

"Up that tree," said the boy discourteously, directing to a neighbouring tree.

You're looking for trouble, aren't you?" said the police officer.

"No, trouble is looking for me!" the boy answered solemnly.

Why is the boy behaving like this?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

What goes up but never comes down?