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Logic

Introduction

Truth-Seeking

           

Suppose you are visiting an island with knights who always tell the truth, knaves who always lie, and jokers who can do either.

What must the islander depicted above be?

There are many variants of truth-teller and liar puzzles in this exploration, including advanced challenges featuring further types of tricksters such as werewolves, jokers, and pirates.

There's even a later quiz that builds up to a challenge known as "the hardest logic puzzle ever!"

Suppose you are visiting an island with knights who always tell the truth, knaves who always lie, and jokers who can do either.

You meet three islanders named Ellis, Farin, and Gobi. They all know what each other is (a knight, knave or joker) and make the following statements:

If exactly one of them is a joker, how many of them are knights?

There are 3 boxes, exactly one of which has a car. You can keep the car if you pick the correct box!

On each box there is a statement, exactly one of which is true.

Box 1: The car is in this box.
Box 2: The car is not in this box.
Box 3: The car is not in box 1.

Which box has the car?

You have four closed boxes as shown:

While you know all four types of food are inside and each box only contains one type of food, you also know that only one of the boxes is labeled correctly. What's the minimum number of boxes that you need to open to be guaranteed (regardless of luck) to find out which one is labeled correctly?

In front of you are 3 chests, labeled as shown:

You are told that all of the labels are incorrectly placed. Each label describes the contents of a different chest. To determine which chest contains 100 gold coins, you are allowed to pick a single random coin from a chest of your choice.

Which chest should you pick a coin from?

Note: The picking of a single coin is just a sample to figure out where the 100 gold coins are. The single coin is random, you don't get to look inside. Plus the chest you choose to pick the coin from does not, necessarily, need to be the chest of 100 gold coins. You're picking a chest first to determine which chest it is that has 100 gold coins in it.

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