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

What does this Rebus Picture mean?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Make a sentence consisting of three words that have the whole alphabet.

Solve the following series:
AZ, GT, MN, __, YB

If six children and two dogs were under an umbrella, how come none of them got wet?

You know three triplets: Frank John and Wayne (need to return your money). Frank always tells the truth while John and Wayne always lie. You meet one of them on the road and can ask him a three-word question.
Which question, will you ask?

A man is shown a portrait painting. He looks closely, then tells, “Brothers and sisters have I none, but that man’s father is my father’s son!” Who is the man in the portrait?