I still haven’t solved that math riddle, and I pretty much gave up on it. Maybe if I was in high school I could do it, but like you all said, there’s probably a trick to it. If there is, I’ll introduce that kid to the floor.
New shorts: ZNH (13.30) @ 1/2
Been watching this one. Rallied nicely after digesting news that flights from mainland China to Taiwan began (http://news.xinhuanet.com/english/2008-12/15/content_10504688_1.htm). Since then ZNH stock flight was delayed until March after heavy turbulence in the market.
This is a plane, not a rocket ship, so why has it blasted off 80% in about one month. Ay yai yai.
Not even tables work. 🙁
| 2 | x | 1.5 | 2.5 | 4 |
| 3 | 0.666667 | x | 1.666667 | 2.666667 |
| 5 | 0.4 | 0.6 | x | 1.6 |
| 8 | 0.25 | 0.375 | 0.625 | x |
| 15 | 0.133333 | 0.2 | x | x |
| 11 | 0.181818 | x | 0.454545 | x |
| 10 | x | 0.3 | 0.5 | x |
| 7 | x | 0.428571 | x | 1.142857 |
| 6 | x | 0.5 | 0.833333 | x |
| 1 | x | x | 5 | 8 |
| 2 | 3 | 5 | 8 | |
| 0.666667 | x | x | 0.133333 | 0.083333 |
| 0.4 | x | 0.133333 | x | 0.05 |
| 0.25 | x | 0.083333 | 0.05 | x |
| 1.5 | x | x | 0.3 | 0.1875 |
| 2.5 | x | 0.833333 | x | 0.3125 |
| 0.6 | 0.3 | x | x | 0.075 |
| 0.375 | 0.1875 | 0.125 | x | x |
| 0.625 | 0.3125 | 0.208333 | x | x |
| 1.666667 | 0.833333 | x | x | 0.208333 |
| 4 | x | 1.333333 | 0.8 | x |
| 2.666667 | 1.333333 | x | 0.533333 | x |
| 1.6 | 0.8 | 0.533333 | x | x |
O.K grabbed some of this short with you .
This can move up on light light volume, so try to stomach it if it does.
I ran another script and got 234 unique answers… none of them being 36 or -36
…
-39.33333333
-39
-38.5
-36.66666667
-35
-34.66666667
…
33
34
35
37
38
38.5
39
39.33333333
…
yeomps, u do programming? I reversed-engineered it too and got some of those answers. but i left out that last set so i’m gonna try it tonight. it’s kind of neat though that we can get almost every other number BUT 36.
btw, the kid said this question was from his teacher, and for about 3 days no one solved it. 5th grade. LOL. I assume there is a solution, otherwise, his teacher will get spammed. Literal, physical, SPAM.
(all your numbers in comment show up on my phone, but not on the internet. strange.)
Gio, I’m a Mechanical Engineer but I program databases/webpages on the side. The script that I wrote was very vulgar… but it works alright for a little hack. It works like this:
randomly choose ‘a’ from 2,3,5,8
randomly choose ‘s1’ from +,-,x,/
randomly choose ‘b’ from 3 remaining values
randomly choose ‘s2’ from +,-,x,/
randomly choose ‘c’ from 2 remaining values
randomly choose ‘s3’ from +,-,x,/
randomly choose ‘d’ as remaining values
calculate: a s1 b s2 c s3 d = calc1
calculate: (a s1 b) s2 (c s3 d) = calc2
lather, rinse, repeat… ad nauseum.
yeomps, why don’t you just iterate through all the possibilities?
that being said, i have a hunch that it is unsolvable. my guess is that little twerp gave you a bad problem statement or there is an asinine loophole in it somewhere.
4! * 4! = (576) total possibilities, no?
It is actually 4! * 4^3 * 2 * 2(the first factor of two comes from putting a ‘-‘ on the initial number and the second from the fact that an answer can be calculated by way of calc1 & calc2… see above). This makes something more like 6000 possibilities…
However, 2+3+5+8 is the same as 3+2+5+8… and so on… so that there are maybe only 200-300 UNIQUE solutions
I didn’t iterate because I programmed it with php in like 10 minutes (during a break from writing a site back-end) and I didn’t feel like writing the proper classes to do it the right way…. Randomly picking a symbol and then executing would have taken me another 10-20 minutes… so I just shuffled the array 2,3,5,8 and picked them in order and used nested loops for the symbols… the results were stored in an array such that array[answer] = answer…. this auto deletes duplicates/near duplicates (rounding errors)… And now I’ve spent more time writing about it than I did actually writing it.
Yeah, if anyone solves that without brute forcing it (trying every combination), you can claim one million dollars. This is an example of a P = NP Problem (third paragraph explaining adding up numbers — this example is just marginally more complex with more symbols). The only way to solve this kind of problem is to brute force it and try every single answer one by one (minus optimizations).
Additionally, if this problem is solved, then you are a potential target for all sorts of criminal elements and black-ops organizations, as you have now defeated cryptography and all bank accounts and secure transmissions are in jeopardy.
I suspect the person who gave you the problem is screwing with you. 😛
the kid is definitely fucking with you.
results in CSV format
here you go, I do believe the kid is messing with you.
The kid is definitely messing with you. here’s the results in CSV format(note that order of operations DO NOT TAKE PRECEDENCE, it’s left to right, all combinations are still tested anyways, you can find the order-of-operations friendly equivalent elsewhere in the file)
sorry about the multiple posts, my connection was a little wonky or something
Damn, seriously I apologize, one more try:
Here’s the results where the operators are not unique (the previous one had unique numbers and unique operators (* / + -))
sihylm:
nice job iterating… however there are a few small issues…
first: at times you are only choosing 2 or 3 number instead of all 4 (example: 2+3+5=10).
second: how do you account for something like (2+3)*(5+8)?
finally: the ‘-‘ variable is ignored (2+3)*(-(5+8))
I’ve been thinking about that last one for the last few minutes… it may play a significant role… but I believe that with only invert the sign of the answer no matter where it is placed.
As a side note… I’ve been certain that this whole 36 answer was a trick… but I think the fun is in defining the means to a solution. (I still say it is 23+5+8)
nice! good point yeomps!
Here are the results when I include negatives:
http://stashbox.org/497680/results.csv
Note: This isn’t solved with your second question of order of operations regarding parentheses (that would make it significantly harder). At this point it’s more worth it for me to optimize logically: The prime factors for 36 are 2x2x3x3. The only time parallel order of operations is useful in four numbers and only: (a+b)*(x+y), as you said earlier. E.g. (a+b*(x+y)) is covered as “y + x * b + a”. In the case of (a+b)*(x+y), that leaves the prime factors to be considered, which means that it has to equal (9)*(4), (2)*(18), (3)*(12) or (6)*(6), which is impossible with the numbers given.
It probably is some garbage 23+5+8 (if so, please deprive the kid out of ice cream for making such a lame joke)
covered ZNH for over 2 pts
Me too. Thanks Gio. Its good to have you back.
Thank you very much for the pick [znh] . I lived in Hawaii in 1983-5 . In Oahu . A condo in Discovery bay [above the rat infested Mcdonalds]. Probably was the healthiest I ever was, luv the air . Sold my condo in 1990 when the Japanese pushed the market up. Luckiest play I every did . Went to Mauii for halloween last Oct . Then to Hapuna Princess on big island . You live in a great place. Unfortunately I felt like a Howlly on a rock!!
Good job guys. still holding.
@mastergain… nice timing on the real estate. I’m still wondering if I should invest in real estate here, but I think the prices will go down even more. The bank asking for 20% down, so a lot of people can’ afford.
Gio when I was in Mauii . I want up HALEAKALA . I never saw so many for sale signs . Your lucky to not own , right now .