Puzzle Archives - Puzzle Prime

Geek/X Puzzle Hunt

Section: Article Category: Discovery

Our friends at Geek_X, an Australian company for high-quality geek stuff, recently created a fun interactive puzzle hunt. To solve it, visit the link from the video below…

or simply CLICK HERE.

Puzzle Prime July 31, 2020

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Knights and Coins

Section: Brain Teasers Category: Insight

Difficulty: Hard

Bob and Jane are taking turns, placing knights and coins respectively on a chessboard. If Bob is allowed to place a knight only on an empty square which is not attacked by another knight, how many pieces at most can he place before running out of moves? Assume that Jane starts second and plays optimally, trying to prevent Bob from placing knights on the board.

SOLUTION

Bob can place at most 16 knights. One way to do this is to keep placing knights only on the 32 white squares. In order to see that Jane can prevent Bob from placing more than 16 knights, split the board in four 4×4 grids. Then, group the squares in each grid in pairs, as shown on the image below. If Bob places a knight on any square, then Jane will place a coin on its paired square. This way Bob can place at most one knight on each of the four red squares, one knight on each of the four green squares, one knight on each of the four brown squares, and one knight on each of the four blue squares. Therefore, he can not place more than 64/4 = 16 knights on the board.

Unknown Author July 27, 2020

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Movie Conundrums 3

Section: Casual Puzzles Category: Rebus

Difficulty: Easy Tags: Movie Conundrums

Can you recognize which famous movies are depicted by these images?

SOLUTION

Star Wars
Million Dollars Baby
The Matrix Reloaded

Puzzle Prime July 24, 2020

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Light Bulbs in the Attic

Section: Brain Teasers Category: Insight

Difficulty: Hard

There are three light bulbs in your attic. All of them are turned off and their switches are installed downstairs. You can play with the switches as much as you want and after that, you can visit the attic above just once. How can you find out which switch to which bulb corresponds?

SOLUTION

You turn the first switch on, then wait for 30 minutes and turn the second switch on. After that go upstairs and examine the bulbs. The one which is turned off corresponds to the third switch. The one which is turned on and is still cold corresponds to the second switch. The one which is turned on and is hot corresponds to the first switch.

Unknown Author July 21, 2020

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The Twelve Matchsticks

Section: Brain Teasers Category: Mathematics

Difficulty: Hard Tags: Matchsticks

With 12 matches you can easily create a shape with area 9 and a shape with area 5, as shown on the picture below. Can you rearrange the 12 matchsticks, so that they encompass an area of 4?

Remark: You should have only one resulting shape and no matches should be unused.

SOLUTION

First, create a Pythagorean triangle with sides 3, 4, 5, and area 6. Then simply flip its right angle inwards, so that the area decreases by 2.

Martin Gardner July 18, 2020

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Movie Conundrums 2

Section: Casual Puzzles Category: Rebus

Difficulty: Easy Tags: Movie Conundrums

Can you recognize which famous movies are depicted by these images?

SOLUTION

The Good, the Bad and the Ugly
American Pie
2001: Space Odyssey

Puzzle Prime July 12, 2020

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2 Matchsticks, 4 Squares

Section: Brain Teasers Category: Insight

Difficulty: Medium Tags: Matchsticks

Move only 2 matchsticks so that you get 4 (identical) squares. There should not be any spare matchsticks left.

SOLUTION

The solution is shown below.

Unknown Author July 9, 2020

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Programmers and Coins

Section: Brain Teasers Category: Mathematics

Difficulty: Advanced

One programmer draws on a sheet of paper several circles in a line, representing coins, and puts his thumb on the first circle, covering the rest with his hand. Then he asks another programmer to guess how many different head-tail combinations are possible if someone flips all the (imaginary) coins on the paper. The second programmer, without knowing the number of circles, takes the pen and writes down a number. Then the first programmer lifts his hand and sees that the correct answer is written on the paper. How did the second programmer manage to do this?

SOLUTION

The second programmer wrote down “1” in front of the first circle. When the second programmer lifted his hand, he saw the number “10…00”, which is exactly the number of possible head-tail combinations in binary system.

Unknown Author July 6, 2020

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Nothing Serious

Section: Casual Puzzles Category: Riddle

Difficulty: Easy

When I’m first said,
I’m quite mysterious,
But when I’m explained,
I’m nothing serious.

What am I?

SOLUTION

The answer is RIDDLE.

Unknown Author July 3, 2020

4 Comments

Joseph’s Machines

Section: Article Category: Discovery

Joseph Herscher is a kinetic artist and a YouTube personality, who specializes in creating intricate Rude Goldberg machines out of everyday objects. Some of his most popular machines are “The Page Turner”, “The Dresser”, and “The Cake Server” which you can see below. Joseph has been sharing his inventions on YouTube for more than 10 years, and you can explore all of them on his official channel. Who knows, maybe he will inspire you to start making fascinating Rude Goldberg machines as well!

Puzzle Prime June 30, 2020

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