Can you fill the blank with the correct number?

6 30 870 756030 _____

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?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

Find the next number in the sequence

5 12 24 36 ?

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

When it's bad luck to meet a black cat?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

Peter wakes up daily to pick up his cycle and crosses the border between Spain and France daily with a bag on his shoulder. He is investigated daily by the officials but they don't find anything suspicious.

If we tell you that he is smuggling something what would it be?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

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