You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

Can you count the number of triangles in the picture below?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

While preparing the table for dinner, wife came up with an idea to tease his mathematician husband. She asked her husband to pick nine toothpicks and make ten without breaking any toothpick.

The husband was also smart and did it within seconds. How ?

In the picture, you can see a chess board. On the top left position, the K marks a knight. Now, can you move the knight in a manner that after 63 moves, the knight has been placed at all the squares exactly once excluding the starting square?

What has a bottom at the top?

Imagine you are in a room with no windows or doors. How will you get out?

You’re out on the water and see a boat filled with people. You look away for a second and look back again, but this time you don’t see a single person on the boat. Why? Hint: The boat did not sink.

Can you name some countries which do not have the alphabet 'A' in them?