Can you replace the question mark with the correct number?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

There was a competition where the contestants had to hold something. At the end of the event, the winner was a person who had no hands or feet. What was it that the contestants had to hold?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

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?

Find the last number in the series below:

voN luJ yaM raM ---

A man embarked on a questionnaire game. He kept asking the same question to whomever he found. The answer each time was different.

Can you guess what the question was?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

Alex is stranded on an island covered in forest.
One day, when the wind is blowing from the west, lightning strikes the west end of the island and sets fire to the forest. The fire is very violent, burning everything in its path, and without intervention the fire will burn the whole island, killing the man in the process.

There are cliffs around the island, so he cannot jump off.

How can the Alex survive the fire? (There are no buckets or any other means to put out the fire)

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?