Here's a couple more Logic Puzzles I had posted before, but might as well post again. Most of them come from xkcd forums, so I do not take credit for making these riddles.
Note: These are LOGIC Puzzles. There is no stupid answer or me trying to be clever with wording or how I phrase something. There's nothing really smug about these puzzles and just require brute force logical thinking and rationale. Don't think outside the box in these questions.
Three Princesses (A Labyrinth Puzzle variation)
As a bachelor for the royal court, you must choose between three princesses to marry. The three princesses vary from age. The eldest princess only is able to tell the truth, the youngest princess is only able to tell lies, and the middle sister is mischievous and mentally flips a coin to determine if she lies or tells the truth. The king summons you to his humble palace, and you are greeted with the three princesses standing side by side, unable to physically determine which princess belongs in which age group. Now, the king demands that you make a choice now, but allows you to ask ONE princess ONE question. You want to marry either the eldest or the youngest princess, so that at least you can know where you stand with them.
What one question do you ask in order to avoid marrying the middle princess?
Ask princess A: "Is princess B older than princess C?"
I'll only give you the answer, figure out the logic yourself. It only spoils the fun >:D
You are abducted by the mafia and physically restrained of all movement, sitting on a chair. The mafia boss comes in and decides to toy with your life with a game of russian roulette. He shows you the gun and places two bullets in adjacent positions. He spins the barrel of the gun until it physically stops, then locks and loads the gun. He places the gun on your scalp, and fires. *click* It's an empty chamber. Then he says "I'll set you free if you live through this next shot because lady luck has a thing for you. The only question is, would you like me to fire right now or spin the barrel again before I fire the next shot?"
Which choice guarantees the greatest success of seeing through the ordeal alive?
Yet again, I'll only give you the answer, figure out the logic yourself. It only spoils the fun >:D
The Monty Hall problem
Suppose you’re on a game show and you’re given the choice of three doors. Behind one door is a car; behind the others, goats. The car and the goats were placed randomly behind the doors before the show. The rules of the game show are as follows: After you have chosen a door, the door remains closed for the time being. The game show host, Monty Hall, who knows what is behind the doors, now has to open one of the two remaining doors, and the door he opens must have a goat behind it. If both remaining doors have goats behind them, he chooses one randomly. After Monty Hall opens a door with a goat, he will ask you to decide whether you want to stay with your first choice or to switch to the last remaining door. Imagine that you chose Door 1 and the host opens Door 3, which has a goat. He then asks you “Do you want to switch to Door Number 2?” Is it to your advantage to change your choice? (Krauss and Wang 2003:10)
And figure the logic yourself :P
Devil's Quarter Game
You die, and are brought before the devil to determine whether you will go to heaven or hell.
The Devil says that if you beat him at quarter placement game you can go to heaven. The rules of the game are this:
There is a large circular table. You and the devil each have an unlimited number of quarters. You take turns placing the quarters on the table. The quarters must be laid flat on the table, they cannot hang off the edges, they cannot overlap, but they may touch. A player loses when he cannot make a legal play (i.e. when it is a player's turn, and there is not enough room on the table for them to play another quarter).
The devil plays first, and you realize that you will lose.
What was the devil's first play, and what is his unbeatable strategy?
He played in the center, thus every move you make he will mirror that move.
i.e.: You play 2 inches away from the center, he will then play 2 inches away in the opposite direction of the center, following the diameter made by intersecting those 3 plays.