How can you write nineteen in a manner that if we take out one, it becomes twenty?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

People make me, save me, change me, raise me. What am I?

A Car driver was heading down a street in Washington. He went right past a stop sign without stopping, he turned left where there was a 'no left turn' sign and he went the wrong way on a one-way street. Then he went on the right side of the road past a cop car. Still, he didn't break any traffic laws. Why not?

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle:

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

Forwards I am heavy, backward I am not. What am I?

An exterior architect is asked by a builder to plant seven trees in a manner that there are exactly six rows of trees in a straight line and each row has three trees in particular.

How will he do it?

If 24H in a D => 24 hours in a day.
What does "64S on CB" stand for?