Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside.
The man said, "Oh! I am really sorry, I thought this was my room."
He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man.
What made her suspicious of that man? He might have been genuinely mistaken.

Suppose that you are trapped on the surface of a frozen lake. The surface is so smooth and ideal that there is no friction at all. You cant make any grip on the ice and no wind is blowing to help you out. You have just a mobile phone with you which has got no reception disabling you to call for help.

How will you plan your escape before you freeze to death on the frozen lake?

Why Aeroplane windows are round?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

There is a straight highway. Four different villages lie on that highway. The distance between them is different. The third village is 60km away from the first village; the fourth is 40 km away from the second; the third is 10 km near to the fourth that it is to the second.

Can you calculate the distance between the fourth and the first village ?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

I can write cow in 13 letters.

Can You?

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?