Replace the question mark with the correct number in the below-given picture?

Today is John's birthday.
A year ago, John had five candles and he lit all the candles except the one at the last.
Now he is going to light all the candles.

How old is John Today?

(He is not five today.....)

I am a ten letters word
The first four letters have the power to rule,
Next, four-letter can be eaten.
The next three-letter represents a lady.
I can fly as well

what am I looking for?

Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

What do you answer even though it never asks you questions?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

A man is found dead with a knife in his back When the investigation is done. A chair lays beside him and the forensic team finds moisture around the body.

If he committed suicide, how did he do it?

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?