Skip to main content

New answers tagged

3 votes
Accepted

ORIGAMI: Above and beyond

Found this when originally solving the first few example puzzles.
Magma's user avatar
  • 5,314
2 votes

ORIGAMI PUZZLES completed version

My (still incomplete) set of solution. I assume the 'simultaneous folds' at 10 and 30 are allowed?! (note: blue folds before green) Nr 10 more detailed:
Retudin's user avatar
  • 9,198
4 votes

ORIGAMI PUZZLES completed version

Here are my partial answers. With some differences from PDT's. Fold on the blue lines. Row 1, #1 to #5 Row 2, #6 to #10 Row 3, #11 to #15 Row 4, #16 to #20 Row 5, #21 to #25 PS: I removed a ...
Florian F's user avatar
  • 30.2k
4 votes
Accepted

Graph needed which satisfy both properties 1 and 2

Graph which has 15 edges (non-drawn matches) This gives the output "CORRECT" when fed to the Python script. Method of solving
fandango96's user avatar
3 votes

ORIGAMI PUZZLES completed version

For the top half this is my progress so far: Row 1 (complete) Row 2: Last is still unsolved and also added steps for 1 and 4 for clarity: Row 3 (complete)
PDT's user avatar
  • 14.7k
0 votes

Infinite Towers of Trouble (with a capital T that rhymes with P...)

First step (revealed in first spoiler) Second step (revealed in second spoiler) Third step Overall On that basis, here are the solutions
hexomino's user avatar
  • 136k
6 votes
Accepted

A "magical" grid progression

The final grid should be shaded because
AxiomaticSystem's user avatar
10 votes

find the 3 digits that calculate the same

msh210's user avatar
  • 12.8k
1 vote

origami J-SHAPED t2

logic: for anyone attempting my original puzzle pack (linked in the question), the spoilered logic is helpful for a lot of puzzles.
Omega_3301's user avatar
0 votes

Weighted Average Question

Let the weights be $a,b,c$. You are given $$a+b+c=1\\11204a+12508b+13280c=12375\\11204a+13508b+13280c=12498$$ Three equations in three unknowns. Subtract the second from the third and $b$ falls out.
Ross Millikan's user avatar
2 votes
Accepted

Flipping DIP switches

If I'm correctly understanding the clarifications given by OP in comments, the situation is as follows: We have to get all 8 switches set correctly. Either the first 4 are already correct, or the ...
Gareth McCaughan's user avatar
1 vote

Flipping DIP switches

In the worst case, there's only one working combination, and it is the last one (256th) you try. This means you have switch to a different combination 255 times. (You don't need to switch anything to ...
Bass's user avatar
  • 77.6k
0 votes

A simple cross-number puzzle # 2

A bit of different approach(more straightforward/bruteforced, less math knowledge) than Bubbler's answer: 1 ACROSS. A prime which is the sum of two squares 3 ACROSS. Twice the answer to 2 DOWN 1 ...
Novarg's user avatar
  • 3,944
4 votes

Shortest battleship game, to find the ships

The optimal answer is Here is the reasoning: I now claim that Hence, Actually, it is even clear that But since
Tim Seifert's user avatar
5 votes
Accepted

A simple cross-number puzzle # 2

1 Down: 1 Across: Alternatively, you can 4 Down & 5 Across: 3 Across & 2 Down: Solution:
Bubbler's user avatar
  • 14.6k
6 votes
Accepted

Shortest battleship game, to find the ships

A quick baseline answer: it is possible to guess of all locations on the grid to find the locations of every ship fragment. It uses the fact that and there are at least two ways to achieve it: ...
Bubbler's user avatar
  • 14.6k
12 votes
Accepted

Making 1353 using Four fours

Here is how you do it:
PDT's user avatar
  • 14.7k
6 votes
Accepted

Gold and silver coins in sealed envelopes

I feel like someone should discuss the axiom of choice in an answer. Bob's strategy First, let's consider a modified puzzle where Alice only has a finite number of gold coins. Here's a strategy Bob ...
tehtmi's user avatar
  • 3,316
7 votes
Accepted

Shortest battleship game, to find number of battleships

Apart from the edges, which require a bit more attention (but whose effect can be made arbitrarily small by increasing the board size), I think this pattern will give an exact ship count with only of ...
Bass's user avatar
  • 77.6k
3 votes

Shortest battleship game, to find number of battleships

What about this strategy? Key: Therefore
Tyler Seacrest's user avatar
3 votes

Shortest battleship game, to find number of battleships

I think this improves on StephenTG's answer. The first player places Then the second player guesses This requires:
Ed Murphy's user avatar
  • 2,142
5 votes

Shortest battleship game, to find number of battleships

Generally, we require For a 7x7 board, this requires 15 guesses on 49 spaces, or guessing 30.6% of the board. For a 77x77 board, this requires 1875/5929 spaces, or 31.6% of the board. In the limit of ...
Nuclear Hoagie's user avatar
3 votes

Shortest battleship game, to find number of battleships

Not sure if optimal, but a marked improvement on the baseline: The first player: Then the second player guesses: This requires us to guess:
StephenTG's user avatar
  • 3,615
3 votes
Accepted

make seven products equal along sides of heptagon

Bonus with extra challenge: Main puzzle with extra challenge:
Bubbler's user avatar
  • 14.6k
4 votes

make seven products equal along sides of heptagon

Firstly Bonus Bonus with a smaller maximum
hexomino's user avatar
  • 136k
0 votes

Geometry Puzzle: Tangent Circles with Integer Radii

In Figure 12, one possible solution is depicted, with radii $1/146$, $1/27$, $1/23$, and $1/18$, respectively. This can easily be scaled by $90666$ times (the LCM) to become integers, namely $621$, $...
Sny's user avatar
  • 3,157
2 votes

make seven products equal along sides of heptagon

You will have the product of each defined by the side and two corners that border it. That product The bonus question
Ross Millikan's user avatar
1 vote

make seven products equal along sides of heptagon

(Note that this is not the only possible solution.)
msh210's user avatar
  • 12.8k
16 votes
Accepted

Gaps Between Ecuadorian Numbers

I believe the largest gap is Here is such an example (there may be an earlier example of a similar sized gap): To see why this is the biggest such gap,
Tyler Seacrest's user avatar
5 votes

Gold and silver coins in sealed envelopes

Bob can't do better than 50%. I admittedly don't follow all the axiom of choice discussion, but intuitively, Bob cannot do better than random chance. All the envelopes are filled independently - the ...
Nuclear Hoagie's user avatar
1 vote

Geometry Puzzle: Tangent Circles with Integer Radii

The closest I've got so far with some very brute force searching is this sequence of radii: 20, 19, 18, 17, 16, 14, 8, 5, 4, 3, 2. The final circle overlaps with the rightmost one by about 5....
Brandan's user avatar
  • 85
8 votes
Accepted

Transferring 9 pegs on a 9x9 grid

21 moves for a 9x9 board My code did a meet-in-the-middle search. 21 moves is optimal. Other board sizes 14 moves for 7x7 Shifting the pegs 2 squares diagonally takes 9 moves. Shifting the pegs 4 ...
Tom Sirgedas's user avatar
  • 1,276
6 votes

Graph needed which satisfy both properties 1 and 2

Here is a very symmetric graph: Property 1: Property 2:
Jaap Scherphuis's user avatar
1 vote

Order matters twice

Notice this very important line: However due to a distraction- which lasted for less than a minute. This means that the original starting time was less than 1 minute because even double of 1 minute ...
Hemant Agarwal's user avatar
4 votes
Accepted

Two digits in one

It's also: Indeed, I have no specific way of knowing if this is in fact the intended answer but it fits with the geometry tag and, quite literally, lateral thinking. If it's not, well there is only ...
Fluorine's user avatar
  • 1,182
1 vote

Two digits in one

It's also the digit...
dhuang's user avatar
  • 735
7 votes
Accepted

origami J-SHAPED t2

Center edges of 3 squares diagonal folds:
z100's user avatar
  • 1,133
10 votes
Accepted

What does this concatenation operator do?

It concatenates… More specifically… Therefore… More fun properties:
Someone's user avatar
  • 748
0 votes

Can you tile a 25 x 25 square with a mixture of 2 x 2 squares and 3 x 3 squares?

A classic problem of:
Omega_3301's user avatar
0 votes

A simple cross-number puzzle

Besides the answer of @DanDan面 here above, I found some more solutions, because This yields the following solutions: EDIT: These solutions are not valid. My error here is that I mistaken "prime ...
Klaas van der Weij's user avatar
11 votes
Accepted

A simple cross-number puzzle

Solved grid: Solution:
DanDan面's user avatar
  • 918
3 votes
Accepted

Locked Door Number Puzzle

To open the front door you will need to input: My reasoning went like this: You can finally open the door, 4 years late on your delivery. And fortunately, nothing went to waste since you had to eat ...
Fluorine's user avatar
  • 1,182
2 votes

Tiling a 16x16 square with 1x4 rectangles

Via integer linear programming, the maximum is... ...
RobPratt's user avatar
  • 13.8k
18 votes
Accepted

Tiling a 16x16 square with 1x4 rectangles

Below a solution in which every gridline splits at least one 1x4 rectangle into 2 regions: Edit Actually, I found an easy pattern that will work on bigger squares as well: white: expandible corner ...
Lezzup's user avatar
  • 6,416
4 votes

Tiling a 16x16 square with 1x4 rectangles

Unless I've misunderstood the requirements, the following is optimal:
fljx's user avatar
  • 16.4k
-1 votes

Can you tile a 25 x 25 square with a mixture of 2 x 2 squares and 3 x 3 squares?

Since the tiles to use are squares they can only fill in a rectangular space. 25x25 is square so the obvious problem isn't an issue. I can only think of 3 ways that these tiles can fill in a square ...
SkySpiral7's user avatar
1 vote

How many Wordle images are there?

I count 238 possible row-colorings: ...
Quuxplusone's user avatar
  • 2,230
50 votes

4,4,2,6,2,10,4,_ sequence from 4th grade packet

Same answer as PDT, just explained differently:
Will Octagon Gibson's user avatar
14 votes
Accepted

4,4,2,6,2,10,4,_ sequence from 4th grade packet

I think the answer is Reason
PDT's user avatar
  • 14.7k

Top 50 recent answers are included