Identify the hidden meaning behind this picture?

What do you get if you add 2 to 100 four times?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

What is black when you buy it, red when you use it, and gray when you throw it away?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

In a classic wine shop, the list of three most popular wines are:
- The cost of 1 French wine bottle: 500$
- The cost of 1 German wine bottle: 100$
- The cost of 20 Dutch wine bottles: 100$

John entered the wine shop and he needs to buy
- All three types of wine bottles.
- Needs to buy Dutch wine bottles in multiples of 20.
- Need to buy 100 wine bottles in total.

John has only 10000$. How many wine bottles of each type, John must buy?

Can you find the missing piece of the Porsche?

A man is found dead in his bathroom naked with blood scattered all around him. The bathroom was locked from the inside and there is no trace of any struggle. There is nothing in the bathroom except his pant with the belt still around and his shirt. Also, the medic team can't find any incision in his body that may have been the reason behind so much blood loss.

The Police department is clueless regarding this murder mystery.
Can you?

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!