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.

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

See the given image carefully. What you have to do is move the blue checkers in the position of the black checkers and vice versa. You are only allowed to move the checker to an adjacent empty space. Do it in the least possible moves.

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

Buy me, smell me or deliver me, I do not change.

Who am I?

You’ll find me on Mercury, Earth, Mars, Jupiter, Saturn, and Uranus. But never Neptune, or Venus. What am I?

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?