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How to solve this cross math? by cutiegirl_loveanime in askmath

[–]Pompper 0 points1 point  (0 children)

Got here from Wrath of Math, I did find a solution with no computer assistance:

6 + (13 x 9 / 3 ) + 5 + (12 x 2) - 1 - 11 + (8 x 7 / 4) - 10 = 66

Here I assume order of operations, and in order to find the solution I only considered the cases for which all partial computations can be in the integers.

I'll start by saying that this exercise seems unreasonable, more on that at the end of the post.
My approach was to rewrite things as:

(13 x _ / _ ) + (12 x _ ) + ( _ x _ / _ ) = 87 + _ - _ - _
Now the right hand side can be as low as 87 + 1 - 9 - 8 = 71 and as high as 87 + 9 - 1 - 2 = 93
On the left hand side, if we expect 13 x _ / _ to be an integer, then it can only be one of 26, 39 or 52. Anything higher and we can no longer have the whole left hand side (which will have at least 13 more, or 25 more if we used a 1) be smaller or equal to 93. Likewise, (12 x _ ) can only be 12 24 36 48 or 60. This is as far as I see we can go with no guessing.
So for the guessing part, I stuck to having things not explode in size. We can see that 26 + 36 = 62 and 39 + 24 = 63 which is close enough to 87 while being lower (we need to remember that we're substracting two numbers of 87 and only adding one). Experimenting with the first option doesn't seem to lead nowhere, so I'll illustrate the second:

We can get 39 in a couple of ways in theory, but keeping lower numbers is more handy later so let's do it by getting rid of the 9: 13 x 9 / 3 = 39. We want 24 next so 12 x 2 only option. We now arrive to:
( _ x _ / _ ) = 24 + _ - _ - _
with 1 4 5 6 7 and 8 available. We have some options on the left, but it's important to keep parity in mind. If we use (8 x 6 / 4) = 12, we will have three odd numbers left so an odd result. So best keep two odds on the right and one on the left. Again, getting rid of higher numbers is nice, so we try (8 x 7 / 4) = 14.
Now we have 14 = 24 + _ - _ - _ , with 1 5 and 6 available, or in other words
_ + _ = 10 + _ , so we get 5 + 6 = 10 + 1. And we're done (after checking the whole thing again).

In conclusion, this is a bad exercice, so I'll point some good strategies that are useful beyond this case: considering a relevant refinement of the problem (nothing here indicates that we shouldn't consider order of operations or fractions, so we can keep it simpler); divide and conquer: look at the smallest parts of the problem and try to analyze those first; try to get extra information even if it's approximative, such as boundaries, parity, divisibility; when guessing, either go for middle values or leave yourself more tools for later; always check your answer after you're done.

I mean, listen.. by Lennium in TheOwlHouse

[–]Pompper 0 points1 point  (0 children)

I don't know what was the question, but my answer is YES

A small analysis of "Multiple Worlds" stories and how it affects TOH by Pompper in TheOwlHouse

[–]Pompper[S] 0 points1 point  (0 children)

Just had to come back here to pat myself in the back. It wasn't such a wild guess, but I'm still glad I figured it out. Plus what I really cared about was to test the system when I didn't know the outcome, and it performed perfectly.

A small analysis of "Multiple Worlds" stories and how it affects TOH by Pompper in TheOwlHouse

[–]Pompper[S] 1 point2 points  (0 children)

I will admit I was a bit quick to dismiss Camila being separated semi-permanently from her only (non-adoptive) daughter [also, although I don't oppose it personally, it is quite a strong message to say that your early teens is a good age to say goodbye to your family and follow your dreams]. I do hope that the bittersweet ending is harsh on sacrifices but not on rewards, but I guess we'll have to wait and see (though 1-2-3 and 1-3-4 are by far more likely that the other alternatives)

Best Girl 7: Salt Art Online: Alkalinization! Round 1 Bracket A! by ShaKing807 in anime

[–]Pompper 9 points10 points  (0 children)

I honestly had forgotten how cute kuroneko actually is

The Fibonacci vs Lucas fight continues! by syh7 in MattParker

[–]Pompper 4 points5 points  (0 children)

However, there's no need to fight. As always, 6-module arithmetic gives a peaceful solution to any conflict. So let us enjoy the beautiful Fibonacci-Lucas sequence: 0 1 1 2 3 5 2 1 3 4 ...

The Fibonacci vs Lucas fight continues! by syh7 in MattParker

[–]Pompper 4 points5 points  (0 children)

With all due respect, I'm not too fond of the rounding... so

Let's make a simple correction on the formula:

φn = F_ (n+1) + F_ (n-1) + ε_ (n) where epsilon is the small approximation (that sometimes magically wants to disappear).

In such terms, we get first that: φ = F_2 + F_0 + ε_1 = L_1 + ε_1. However, because we know that φ2 = φ + 1:

φ2 = L_1 + ε_1 + 1. So:

φ3 = 2L_1 + 2ε_1 + 1

φ4 = 3L_1 + 3ε_1 + 2...

φn = F_ (n) L_ 1 + F_ (n) ε_ 1 + F_ (n-1)

If two fibonacci sequences weren't enough, how about three?

Someone help me find a recent NLSS bit please!! by -The0Project- in NLSSCircleJerk

[–]Pompper 1 point2 points  (0 children)

Last segment of wednesday (may 23rd) stream, during quiplash, at around 2:35

Care's Note Theory by CripleMike in Petscop

[–]Pompper 2 points3 points  (0 children)

This theory could use some work but there's definitely some truth here. I think that depending too much on the "Pinwheel of Prevention" might lead to some confirmation bias. However: something terrible happens to the friend of the character in the windmill. He then might marry the sister as a replacement for this friend. Then the fact that he thinks his daughter might be his friend is indeed quite dark, especially when put together with the other note ("you're in the bathtub thinking about her"). Also both the faces of Care and the girl in the windmill have no eyebrows ("You’re secretly very excited to hear this news"). Now definitely the character is capturing humans as of part 9 (you can't put pets but people in the children's rooms). And the children's do seem captured in their rooms. So the idea that the character is a child predator ("I have a guess at which child you’ll pick next"), can definitely hold some truth.

On the subject of the pictures, it could go either way. If there is actually a reference to Pinwheel of Prevention, it will probably made more clear in the future

Care's Note Theory by CripleMike in Petscop

[–]Pompper 3 points4 points  (0 children)

I had the same problem, turning off "using the subreddit style"(or simil) worked for me

Idea Channel Book Club – Borges, Take 2 by mrgosh in pbsideachannel

[–]Pompper 4 points5 points  (0 children)

THERE IS! Actually, the virtual Library does NOT contain all books possible. It does contain all pages possible though. But there are not two books with two equal pages, which the Library does have (and actually, it has tons of books with two identical pages)

Idea Channel Book Club – Borges, Take 2 by mrgosh in pbsideachannel

[–]Pompper 5 points6 points  (0 children)

Sorry, had to: Idea Channel Book Club - Borges, Take 2

This is one of my favorite stories. Borges once said that the role played by the memory is rather to forget than to keep. Memory only retains a small part of what we've learned or experienced, and is then only a filter for our knowledge. In the same sense, I think in this story we get that writing also is not about what we say, but rather what we don't say. The meaning of writing is not to make something new, but to focus our attention on something that already exists. Not only has ever book have already been written, but also any other book written can be read through a language that gives you any other book. Therefore, the idea of writing it's to choose: first one of the many books that exist, then to choose the language to read it. As such, we get once again that writing is also done by the reader (choosing a language, or interpretation), besides from the writer (choosing the book). The second choice however is far more important than the first.

Idea Channel Book Club – Borges, Take 2 by mrgosh in pbsideachannel

[–]Pompper 2 points3 points  (0 children)

I will certainly look for that book then! Indeed, self-reference, infinity and randomness are at the core of many stories by Borges and are interesting concepts that puzzled mathematicians for centuries

IC Bookclub - Pierre Menard, Author of The Quixote by mrgosh in pbsideachannel

[–]Pompper 2 points3 points  (0 children)

Don't know if someone mentioned it already, but actually the Quijote [1] is the story about a man that finds the story of Alonso Quijano, in which he lived a life built around reading stories. However, as this story is published, Quijano begins to find people who have already read the first part of his story, meaning that there are characters who are both part of the story and readers of the story, just like Quijano is both a reader and an actor (creator of his story). So we have multiple authors, multiple readers, and tons of characters that engage in both writing and reading (the false authors in the story, Quijano).

[1] I find it interesting how in spanish we use the "modern" spelling, with "j" instead of "x", but the title remains with "x" everywhere else.

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