Unanswered Questions
30 questions with no upvoted or accepted answers
22
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0
answers
2k
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REALLY important days in history
@Z. Dailey asks a mathematical puzzle Important days in history... and to come! with a series of dates in years 1973, 1978, 1983, 1992, 2005.
My puzzle asks the question: What is the previous date in ...
- 197
12
votes
0
answers
894
views
Dissecting a figure into 2, 3, 4, and 5 parts but not 6
This figure is divided in 2, 3 and 4 equal parts of same size and shape, but it is not possible to do it in 5 equal parts of same size and shape.
Is it possible to find a figure that can be divided ...
- 886
12
votes
0
answers
1k
views
Hidden message in rap text II: "Ya, a ray 'ave july joy!"
This puzzle is inspired by this one by @LukasRotter. Hopefully you don't mind me using similar (well, basically the same) format as yours, Mr. Rotter! ;)
The same rapper released another teaser for ...
- 336
8
votes
0
answers
277
views
Doubling the cube with rational Meccano strips
In three monographs published in 2006, 2008 and 2014 Gerard 't Hooft considered "Meccano mathematics": how to construct specified distances and regular polygons by a rigid system of ideal ...
- 7,820
7
votes
0
answers
197
views
Can you construct a nonagon with 47 rods?
Stiv's Diabolical Instruments now offers a bundle of exactly 47 equal-length rods that can be joined by hinges at their ends – and only the ends – to form planar linkages (i.e. all hinge axes are ...
- 7,820
6
votes
0
answers
254
views
Sequence puzzle: 3, 9, 27
A twist of the classic sequence game:
A friend asked me to find the rule to this sequence: 3, 9, 27.
I am allowed to suggest other sequences to test if they follow that (unknown to me) rule, to which ...
- 10.3k
6
votes
0
answers
314
views
Looking for a kid's puzzle, cannot remember title
I'm looking for a kids' logical puzzle I saw in a Brazilian puzzle magazine several years ago. A farmer had a square farm with four houses and twelve trees and he wanted to divide it between his four ...
- 35.6k
6
votes
0
answers
302
views
Find the missing element?
I've been trying to solve this for quite some time, can you help me solve it?
This puzzle was made by one of my friend's teachers. This is not copyrighted and cannot be found anywhere on the internet.
...
- 41.7k
5
votes
0
answers
265
views
Longest Fibonacci word
Fibonacci words are defined as $F_0 = a, F_1 = b, F_{n+2} = F_nF_{n+1}$ where $a, b$ are letters. How can you find the longest Fibonacci sub-word in a given string?
Try to solve it in linear time ($O(...
- 151
5
votes
0
answers
264
views
Connect dots on a grid with one continuous line (optimization)
(This question is the third puzzle of the Connect dots puzzle series. You can find the first two puzzles here and here, respectively.
The original question and photos originate from webadventurer. ...
- 1,163
4
votes
0
answers
333
views
Lucas's interesting cipher
Lucas was fooling around with some letters when he encoded some text into Gsobj lwmtkd sbceugb vfy rgdjb.. Can you figure out the original text he had?
4
votes
0
answers
234
views
The smallest number
Some time ago I created a program to generate a table, and printed the first seven rows and columns.
Somehow however I forgot to print the headers and the title of the table.
I only remember that it ...
- 229
4
votes
1
answer
561
views
Formula for the sequence 1, 1, 1, 21, 3, 1, 4, 1, 5, 1, 6, ... if the 21 isn't a mistake
The sequence 1, 1, 1, 21, 3, 1, 4, 1, 5, 1, 6, ... appeared in one of my tutorial sheets in 2019. I assumed that the fourth term, 21, was a mistake (was supposed to be ..., 2, 1, ...) then it made ...
- 10.3k
4
votes
1
answer
660
views
Find next element of the sequence
Source of the question: Taken from the sub-Reddit r/askmath here: https://www.reddit.com/r/askmath/comments/15ar3ne/looking_for_the_answer_to_the_following_sequence/
What is the next element of the ...
- 4,057
3
votes
0
answers
156
views
The Mono-Quantum Condrum
You are presented with a locked box, and on its surface, you notice a sequence of peculiar symbols:
⌬ ⌅ ⊙ ⊡
Next to the symbols, there's an inscription:
...
- 147