what does this below rebus represent identXQQQQQME

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Can you place six X (crosses) in below board without making three in a row in any way ?

You’re out on the water and see a boat filled with people. You look away for a second and look back again, but this time you don’t see a single person on the boat. Why? Hint: The boat did not sink.

If a wheel has 54 spokes, how many spaces are there between the spokes?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

Can you move 2 matchsticks to form four equal sized squares.

A King wants to send the diamond ring to his girlfriend securely. He got multiple locks and their corresponding keys. His girlfriend does not have any keys to these locks and if he sends the key without a lock, the key can be copied in the way. How can King send the ring to his girlfriend securely?

What does it mean?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?