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.

A man escapes from jail using help from his girlfriend. The investigators suspect four girls of being the man's girlfriend.

Out of those four girls, one is his girlfriend who is lying. Two of the girls are completely innocent and are speaking the truth. One of the girls is the man's sister who is helping the girlfriend lie. Following are the statements from all four of them:

Ariana: "Myrna is his girlfriend."
Jane: "Angelina is lying."
Angelina: "Ariana is lying."
Myrna: "Jane is not his sister."

Can you find out who is the man's sister among them?

What will you call your mother's brother's brother-in-law?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

I am the fastest animal but cannot climb the tree. What am I?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

What is more useful when it is broken?

Who is that with a neck and no head, two arms and no hands? What is it?