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

What has to be broken before you can use it?

I have no life, but I can die. What am I?

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?

In an interview, a boy was asked an unusual question 'How two persons sitting with a table in between them can't see each other?' He was unable to reply. Can you?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

Can you spot what's wrong with the following sentence?

PETER WAS ANGRY AT
HIMSELF BECAUSE HE
ACCIDENTALLY LEFT THE
THE KEYS TO HIS CAR
AT HIS FRIEND'S HOUSE.

Three ants are going up a hill, one behind the other. The last ant then says to the other ants, 'There is an ant behind me!'' How come?

What you cannot hold but it is yours?

I know a nine-letter word having only one vowel.
Do you ?