What has a ring but no finger?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

What has lots of eyes, but can’t see?

A woman lives in a skyscraper thirty-six floors high and is served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

What does this rebus means ?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

Can you tell a 3D object that has just two surfaces?

What goes through cities and fields, but never moves?

Bopanna was working on a murder case when he received a message about the location of the murder weapon.
The message was encrypted as below.

"deb mitciv eht edisni neddih si nopaew redrum ehT"

Tell me the location of the murder weapon.