Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

I am lying and I always lie. Tell me whether I am lying or telling the truth.

A little girl goes to the store and buys one dozen eggs. As she is going home, all but three break. How many eggs are left unbroken?

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

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

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?

Can you solve the maths in the below-given picture equation?

A guard is positioned at the one side of the bridge saying ‘A’. His task is to shoot all those who try to leave from ‘A’ to the other side and say ‘B’. He also need to welcome the person who comes from another side ‘B’ to his side ‘A’. The guard comes out of his post every 1 hour and looks down the bridge for any people trying to leave. You are at side ‘A’ and wish to go to another side ‘B’. you also know that it would take 1:45 hr to cross the bridge. How will you cross the bridge?

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

Give it food and it will live; give it water and it will die.