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Did You Find Out? Get the Answer to the Riddle of E-News Issue No. 1, February 2024

2024-02-22

The Island of Liars

Exactly 100 people live on a small island in the middle of the ocean, some of whom always tell the truth and some of whom always lie. A scientist wants to find out more about this peculiarity. So he travels to the island and asks each inhabitant how many liars there are. The first says: "There is one liar on the island", the second says: "There are two liars", and so on. The last one says: "There are 100 liars".

How many liars live on the island?

Solution

There are exactly 99 liars on the island. Each of them says a different number, but only one of them can be right. Since some of the inhabitants always lie, while others always tell the truth, only one inhabitant can have told the truth—namely the 99th inhabitant who said: "There are 99 liars on the island".

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