You have an empty wine bottle with a cork that has been secured at the top in a normal way. There is a metal ring inside the bottle that is suspended by a string.

How can you make the metal ring drop to the bottom if you are not allowed to touch anything - not the bottle, not the cork, not the thread and not the ring?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

It spends most of its day eating white, but when it’s quick enough, it gets to eat fruit and sometimes some blue things. It’s in a dark room, where the walls are blue, it runs from a ghost that roams the halls and haunts it all the time. What is it?

The more of this there is, the less you see. What is it?

What number should come in place of the question mark below?

How is the moon similar to a dollar?

I have branches, but no fruit, trunk or leaves. What am I?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

How many letters are in the alphabet?

You need to move three matchsticks to form three squares. Can you do it?