What is full of holes but still holds water?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle:

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

What brings you down but never up?

Which number should replace the question mark?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

Find the next number in the sequence

5 12 24 36 ?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

How do you go from 98 to 720 using just one letter?