Can you replace the question mark with the correct number?

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.

You can win me and lose me but never buy me
You can not eat me and never want to part with me
I can make you cry or bring you joy
I am not a machine and definitely not a toy
You keep me but i am not forever just yours
You might find me in a case or on a shelf next to a vase
I am hard and i am tall if you bump me i am sure to fall
I am made of different materials and am at many events
If your lucky and fight hard I might be yours
What am I ?

The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

What is always in front of you but can’t be seen?

2, 3, 5, 9, 17, _ What is the next number in the sequence?

What is the riddle which can be asked all day with a different correct answer each time.

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

There was a strange boy who was born before his father. How can this be possible?

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