How many times can you subtract the number two from the number fifty?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

Outside a tattoo artist's shop, there was a signboard which read 'I make tattoos on only them who do not tattoo themselves'.

Reading it what do you think, does the tattoo artist tattoo himself?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

What is next number in the pattern below:

131 517 192 123 ?

On a bus, there is a 26-year-old pregnant lady.
A 30-year-old policeman.
A 52-year-old random woman.
And the 65-year-old driver.

Who is the youngest?

How can a man go eight days without sleep?