How can a man go eight days without sleep?

An inspection by the superintendent of St. Joseph School was scheduled on the next day. The class teacher Jenifer knew that he would be asking questions from her class and she would have to choose a pupil to answer. To offer a perfect impression over him, the teacher explained certain instructions to the students to maximise the chances of getting correct answer every time.

What did she say to the students?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

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.

Okay before we begin with the puzzle, do keep in mind that you have to answer it quickly.

You are participating in a car race. Seeking the perfect moment, you overtake the second person in the race. What positions are you in now?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

You can see it everyday, But cannot touch it at will. What is it?

I am soft and cuddly that soothe your heart. But, If you pick my last name I am going to tear you all apart. Who am I?

A system error causes the change of John's net banking password. To sort this out, he calls the customer care. The following is the conversation he had with the executive:

John: My password has been changed.

Custom Care Executive: We have kept your password distinct this time. It has 8 letters out of which, 3 letters are the same as the previous one.

John: Okay, thanks.

Can you determine the old as well as the new password of John's net banking account after reading the conversation carefully?