What does the below image rebus riddle means ?

You throw me out when you want to use me and you take me in when you don't want to use me.

Who Am I?

Replace the question mark with the correct number in below Picture:

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

Women do it once a year after they turn 19 but men get to do it only once in a lifetime. What is it?

It spends most of its day eating white, but when it’s quick enough, it gets to eat fruit and sometimes some blue things. It’s in a dark room, where the walls are blue, it runs from a ghost that roams the halls and haunts it all the time. What is it?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

In the picture that is attached with this question, you can find a square which comprises of four little squares inside it. Consider this square to be made with matchsticks. You have to remove two matchsticks such that only two squares remain instead of five.How will you do it ?