Find out the missing number in the picture attached:

Which alphabet letter is a question?

What always comes into a house through the keyhole?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

I am Huge on Sunday and Saturday.
I am small from Tuesday to Thursday.
I do not exist on Monday and Friday.
Who am I?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

I have a big mouth and I am also quite loud! I am NOT a gossip but I do get involved with everyone's dirty business.

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

Find the Odd One Out?
84129
32418
47632
36119
67626
72927

I have thought of a number that is made up by using all the ten digits just once. Here are a few clues for you to guess my number:

First digits is divisible by 1.
First two digits are divisible by 2.
First three digits are divisible by 3.
First four digits are divisible by 4.
First five digits are divisible by 5.
First six digits are divisible by 6.
First seven digits are divisible by 7.
First eight digits are divisible by 8.
First nine digits are divisible by 9.
The number is divisible by 10.

Can you find out the number ?