What is the next number in this matchsticks series riddle?

A woman is sitting in her hotel room and hears a knock at the door. She opens the door to see a man whom she’s never met before. He says, “I’m sorry, I have made a mistake, I thought this was my room.” He then goes down the corridor and into the elevator. The woman goes back into her room and calls security. What made the woman so suspicious of the man?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

It is a six-letter word.
The first four letters are me.
The second and last letters are the same.
The fourth second and last letter is payment.

Who is it?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

What does this below rebus puzzle mean?

Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?