John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

What can you see in the middle of March and April that you can never see in any other month?

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.

Can you identify if it's a murder or a suicide ?

The peacock is a bird that does not lay eggs. How do they get baby peacocks?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

Before reading ahead, you must know the fact that only one of the people here is telling the truth.

A says that B is lying.
B says that C is lying.
C says both A and B are lying.

Can you find out who is speaking the truth?

That attorney is my brother, testified the accountant.

But the attorney testified he didn't have a brother.

Who is lying?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?