Category: Brain Teasers

A collection of Math, Chess, Detective, Lateral, Insight, Science, Practical, and Deduction puzzles, carefully curated by Puzzle Prime.

Raymond Smullyan

Raymond Merrill Smullyan (1919 – 2017) was an American mathematician, magician, concert pianist, logician, Taoist, and philosopher. Born in Far Rockaway, New York, his first career was stage magic. He earned a BSc from the University of Chicago in 1955 and his Ph.D. from Princeton University in 1959. He is one of many logicians to have studied with Alonzo Church.

Queen’s Death

Section: Brain Teasers Category: Chess

Difficulty: Hard

On which spot was the white queen captured?

SOLUTION

Since the pawns on e6 and h6 have taken 2 of the White’s pieces, and the only two white pieces which could get there are the knight and the queen, the answer is one of these two squares. Similarly, the pawn on b3 should have taken the Black’s c8 bishop, and this should have happened before the White’s queen was taken. Therefore first the white knight was taken on e6, then the black bishop on b3, and finally the white queen on h6.

Raymond Smullyan September 28, 2017

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Chiming Wall Clock

Section: Brain Teasers Category: Deduction

Difficulty: Medium

Your grandma’s wall clock chimes the appropriate number of times at every whole hour, and also once every 15 minutes. If you hear the wall clock chime once, how much more time do you need to figure out what the time is, without looking at it?

SOLUTION

1 hour and 30 minutes. The wall clock will chime once at 12:15, 12:30, 12:45, 1:00, 1:15, 1:30, 1:45. If you hear 7 consecutive times just 1 chime, then the time is 1:45. If you hear less than that, you will easily find what the time is once again.

Unknown Author September 22, 2017

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Light It Up

Section: Brain Teasers Category: Insight

Difficulty: Easy

If you have one match and enter a room in which there is a stove, a kerosine lamp, and an oil burner, what will you light up first?

SOLUTION

The match.

Unknown Author September 19, 2017

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4 builders, 4 houses

Section: Brain Teasers Category: Deduction

Difficulty: Easy

If it takes four months for four builders to build four houses, how many months it will take for two builders to build two houses?

SOLUTION

It will still take four months (not two).

Unknown Author September 16, 2017

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Deadly Vodka

Section: Brain Teasers Category: Lateral

Difficulty: Hard

Two politicians go to a bar and order two glasses of vodka on the rocks. The first politician quickly empties his glass, then orders a second one, a third one… The second politician patiently drinks his own vodka, but about 20 minutes later, he drops down dead. The police discovered that the barman tried to assassinate both politicians, but how come the second one died and the first one lived?

SOLUTION

The poison was in the ice cubes, so the second politician drank them when they melted in his drink.

Unknown Author September 13, 2017

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Careless Truck Driver

Section: Brain Teasers Category: Lateral

Difficulty: Medium

A truck driver was going the opposite way on a one-way street, but no policeman stopped him, even though few of them saw what he was doing. Why?

SOLUTION

Because the truck driver was just a pedestrian on that day, not driving his truck.

Unknown Author September 10, 2017

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Puddle of Water

Section: Brain Teasers Category: Lateral

Difficulty: Medium

A man is found in a room without any windows, with just one door which is locked from the inside. The man is hanging from a ceiling fan, dead, 4 feet above the floor. The room is completely empty, except for the man, the fan, and a puddle of water on the floor. How did the man die?

SOLUTION

The man used a block of ice so that he could hang himself, and then the ice melted into the puddle of water.

Unknown Author September 7, 2017

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Chess Cylinder

Section: Brain Teasers Category: Chess

Difficulty: Medium

Imagine the following game occurs on a cylindrical board, on which the a-file and h-file are attached to each other. White plays first and mates Black in 2 moves.

SOLUTION

White plays Rook on a5, then Ra1#. He can’t take the pawn on a6, because Black will take back with the pawn on h7.

Unknown Author September 1, 2017

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Half Empty, Half Full

Section: Brain Teasers Category: Insight

Difficulty: Advanced

You have a glass with perfectly cylindrical shape which has some water in it. How can you figure out if the glass is exactly half full without using any measurement tools (like a ruler)?

SOLUTION

Use the geometry of the cylinder. Start tilting the glass until the water surface gets either to the top or the bottom edge. If the glass is exactly half full, then the surface should touch both edges simultaneously.

Unknown Author August 28, 2017

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Single Word

Section: Brain Teasers Category: Insight

Difficulty: Advanced

Cross out nine letters so that the remaining letters spell a single word.

N A I S N I E N L G E L T E T W E O R R S D

SOLUTION

Cross out every other letter starting with the first one – N I N E L E T T E R S.

The remaining letters are – A S I N G L E W O R D.

Unknown Author August 22, 2017

2 Comments