Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

Who has married many women but was never married?

How far can you walk into the woods?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

What brings you down but never up?

I inserted a coin in a bottle and closed its mouth with the help of a cork. Now, I was able to take the coin out from the bottle without taking out the cork or breaking the bottle. Can you tell me how I did it?