My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

Find the missing value of "?" in the letter sequence below.

CAD
EBG
KBM
OCR
DDH
NL?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

What does this rebus riddle mean?

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

I look at you, you look at me, I raise my right, you raise your left. What am I?

Take one out and scratch my head, I am now black but once was red. What am I?

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

What does below pictogram mean?