Why do you find that most of the buildings are deprived of the 13th floor?

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

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

What is full of holes but still holds water?

For an extra income, John decided to work at a Hotel for one hour daily. The manager offers him that they will pay him $11 after every 11 days.
However, John offered a different proposition to the manager. The offers stand as:
He will be paid just a penny on his first day.
Two pence will be paid on the second day,
Four pence will be paid on the third day.
And so on till the 11th day.

Should the Hotel manager accept his offer?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

You need to arrange three 7 and mathematical symbols to form number 1?

If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?

A Man gave one of his sons 10 cents and another son was given 15 cents. What time is it?
Hint: Figure out the relation between time and number, is not so easy..:)

A pack of cards has 40 cards. You are blindfolded. Out of 40, 25 cards are facing down while 15 are facing up. You have been asked to divide this pack of cards into two decks - so that each deck contains an equal number of face-up cards. Remember, you are blindfolded.

How will you do it?