Puzzle Archives - Puzzle Prime

The Master Theorem

Section: Article Category: Discovery

In case you have never heard about “the secret society of puzzle solvers” at The Master Theorem, then get ready to face about 50 of the most creative, challenging and original puzzles you can find on the web. Even though the website rarely has been updated in the last few years, it can offer tens of hours of problem solving to all newcomers. In order to sign up and explore everything TMT has to offer, you must first complete one of the numerous puzzles posted there. An easy one you can start with is “Old McDonald”, which can be solved using this… SPOILER.

Puzzle Prime June 17, 2018

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Professor Al’s Books

Section: Brain Teasers Category: Insight

Difficulty: Medium

Professor Al has put the “Lord of the Rings” trilogy books on his shelf in order, next to each other. The books are hard copies, with pages which are 1/100in thick and covers which are 1/8in thick. A worm is eating its way from the first page of the first volume to the last page of the third volume. If each of the volumes contains 400 pages, how long this distance is?

SOLUTION

The first page of the first volume and the last page of the third volume are separated only by the second volume and the extra 2 book covers. Therefore the distance is 4in + 0.5in = 4.5 inches long.

Unknown Author June 17, 2018

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London Escalators

Section: Brain Teasers Category: Lateral

Difficulty: Advanced

In London, many Underground tube stations have two escalators going up, but just one going down. Why?

SOLUTION

This is because when people leave the train, they pack into groups, whereas when they go to catch the train, their flow is evener.

Unknown Author June 10, 2018

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Puzzle Sum 11

Section: Casual Puzzles Category: Rebus

Difficulty: Easy

What bird does this sum spell?

SOLUTION

STAR + TREE + SLING – TREES = STARLING

Sam Loyd June 6, 2018

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King Octopus and His Servants

Section: Brain Teasers Category: Deduction

Difficulty: Medium

King Octopus has servants with 6, 7, or 8 legs. The servants with 7 legs always lie, and the servants with 6 or 8 legs always tell the truth. One day four of the king’s servants had the following conversation:

“We together have 28 legs,” said the first octopus.
“We together have 27 legs,” said the second octopus.
“We together have 26 legs,” said the third octopus.
“We together have 25 legs,” said the fourth octopus.

Which of the four servants told the truth?

SOLUTION

If all four octopuses lied, then their total number of legs must be 28, which is impossible. Therefore exactly one of them said the truth, and the other three had 7 legs each. Since the truthful octopus must have 6 or 8 legs, and 21 + 8 = 29, we see that it has exactly 6 legs, and therefore it is the second one.

Unknown Author June 5, 2018

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The Magnetic Rod

Section: Brain Teasers Category: Science

Difficulty: Advanced

You are in a room with nothing else but two indistinguishable iron rods. You know that one of them is magnetized, how can you figure out which one?

SOLUTION

Touch the middle of the first rod with the end of the second rod. If the two rods get attracted to each other, then the second one is the magnet. If not, then the first one is the magnet.

Martin Gardner June 4, 2018

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Getting Older

Section: Brain Teasers Category: Insight

Difficulty: Medium

If the day before yesterday Tim was 18 years old and next year he will be 21 years old, what is the date today?

SOLUTION

Today is 1st of January.

Unknown Author May 28, 2018

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Along O’Brien’s Bridge

Section: Casual Puzzles Category: Maze

Difficulty: Medium

Get from START to FINISH in this landscape maze, created by Matthew Haussler.

SOLUTION

The solution is shown below.

Matthew Haussler May 26, 2018

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Every Song

Section: Brain Teasers Category: Insight

Difficulty: Medium

John: “I know every song in the World.”

Paul: “It can’t be. I bet you don’t know any songs which contain the name of my daughter – Beatrice.”

John accepted the bet and won. Which song did he sing?

SOLUTION

John performed the “Happy Birthday” song.

Puzzle Prime May 26, 2018

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Place a Coin

Section: Brain Teasers Category: Insight

Difficulty: Advanced

Two friends are playing the following game – taking turns, they place identical coins on a square table, so that no two coins touch each other. Whoever can not make a move, loses the game. Who has a winning strategy?

SOLUTION

The first player has a winning strategy. He just has to place the first coin in the center of the table and then each consecutive one symmetrically opposite to the last coin of his opponent.

Unknown Author May 25, 2018

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