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

Which number comes next in the number series?

2, 9, 30, 93, ?

The captain of a ship is telling you an interesting story and then poses a question. He says, “I have travelled the oceans far and wide. One time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly. Can you tell me how that was possible?”

It is a nine-letter word.
The exact opposite of the phrase "friendly and outgoing"
It contains the word "over".
It starts will a vowel.

What is it?

A man dies of old age on his 25 birthday. How is this possible?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

What is the centre of gravity?