In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

Before Mount Everest was discovered, what was the highest mountain in the world?

What can go through glass without breaking it?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

A sea diver is a real show-off. He showed everyone that he can hold his breath underwater for 15 minutes.

I went to the diver and told him that I can be underwater for double the time i.e 30 minutes.
He responded that he will give me 100$ if I would be able to do it. I won 100$.

What did I do?

Which is heavier: a ton of bricks or a ton of feathers?

There was a strange boy who was born before his father. How can this be possible?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

Two guards were guarding the camp.Guard-1 was looking towards the south to make sure no threat is coming from the road.Guard-2 was looking at the north to make sure no threat is coming from the top. Suddenly Guard-1 ask the Guard-2 why he is smiling?How Guard-1 knows that Guard-2 is smiling?

Can you place six X (crosses) in below board without making three in a row in any way ?