There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.
If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.
Will you accept that bet?
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 was driving a black truck. His lights were not on. The moon was not out. A lady was crossing the street. How did the man see her?
In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?
Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?
? : 3839 :: 11 : 1209
You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?
Why are televisions attracted to people?
I have an eye but still cannot see.
Who am I?
Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?
What is both possible and impossible at the same time?
Give it food and it will live; give it water and it will die.
There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.
