Logic Puzzles

Puzzles that can only be solved by thinking logically.

Three doors to choose from

The “Monty Hall” problem was made famous when it appeared in Parade magazine’s “Ask Marilyn” column in 1990, and it was so counterintuitive it had everyone from high school students to top mathematical minds questioning the answer—but rest assured, the solution is accurate. Named for the Let’s Make a Deal game show host, the puzzle goes like this: You are given three doors to choose from, one of which contains a car and the other two contain goats. After you’ve chosen one but haven’t opened it, Monty, who knows where everything is, reveals the location of a goat from behind one of the other two doors. Should you stick with your original choice or switch, if you want the car?

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Average: 8 (1 vote)

There are three bags

There are three bags, each containing two marbles. Bag A contains two white marbles, Bag B contains two black marbles, and Bag C contains one white marble and one black marble. You pick a random bag and take out one marble, which is white. What is the probability that the remaining marble from the same bag is also white?

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Average: 8 (1 vote)

There is a barrel with no lid

There is a barrel with no lid and some wine in it. “This barrel of wine is more than half full,” says the woman. “No, it’s not,” says the man. “It’s less than half full.” Without any measuring implements and without removing any wine from the barrel, how can they easily determine who is correct?

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Average: 8 (1 vote)

Catching mice

If five cats can catch five mice in five minutes, how long will it take one cat to catch one mouse?

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Average: 8 (1 vote)

On the king’s property

This one could also fall in the lying/truth category. A man is caught on the king’s property. He is brought before the king to be punished. The king says, “You must give me a statement. If it is true, you will be killed by lions. If it is false, you will be killed by trampling of wild buffalo. If I can’t figure it out, I’ll have to let you go.” Sure enough, the man was released. What was the man’s statement?

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Average: 8 (1 vote)

Four people

Let’s pretend we’re on the metric system and use kilograms instead of pounds to give us a starting base number of 100. Four people (Alex, Brook, Chris and Dusty) want to cross a river in a boat that can only carry 100kg. Alex weighs 90kg, Brook weighs 80kg, Chris weighs 60kg and Dusty weighs 40kg, and they have 20kg of supplies. How do they get across?

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Average: 8 (1 vote)

A farmer wants to cross a river

A farmer wants to cross a river and take with him a wolf, a goat and a cabbage. He has a boat, but it can only fit himself plus either the wolf, the goat or the cabbage. If the wolf and the goat are alone on one shore, the wolf will eat the goat. If the goat and the cabbage are alone on the shore, the goat will eat the cabbage. How can the farmer bring the wolf, the goat and the cabbage across the river without anything being eaten?

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Average: 5.7 (3 votes)