A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?
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.
If six children and two dogs were under an umbrella, how come none of them got wet?
You need to arrange three 7 and mathematical symbols to form number 1?
As a whole I am both
safe and secure.
Behead me and I become
a place of meeting.
Behead me again and I am
the partner of ready.
Restore me, and I become
the domain of beasts.
What am I?
What is common among 11, 69, and 88?
A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?
You have four chains. Each chain has three links in it. Although it is difficult to cut the links, you wish to make a single loop with all 12 links. What is the fewest number of cuts you must make to accomplish this task?
Three people enter a room and have a green or blue hat placed on their heads. They cannot see their own hat but can see the other hats.
The colour of each hat is purely random. They could all be green, blue, or any combination of green and blue.
They need to guess their own hat colour by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $10,000 each, but if anyone guesses incorrectly they all get nothing.
What is the best strategy?
John asked Jack, "The time right now is 7 pm. Can you tell me what will be the time 23, 999, 995 hours later ?"
While Bella does not know the answer, do you ?
Which number should replace the question mark?
In Canada, a mathematical puzzle must be solved in order to win the lottery to classify it as a “game of skill” not gambling.