How can you make a TV, a bed, a dog, and a car liquid?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

What came first, the chicken or the egg?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

A boy and his father are caught in a traffic accident, and the father dies. Immediately the boy is rushed to a hospital, suffering from injuries. But the attending surgeon at the hospital, upon seeing the boy, says 'I cannot operate. This boy is my son.' How is this situation explained?

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different. How do you measure 45 minutes?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

Which of the following words don't belong in the group and why?
CORSET, COSTER, SECTOR, ESCORT, COURTS