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I know you think about me before bedtime. — Parallax Forums

I know you think about me before bedtime.

ReachReach Posts: 107
edited 2014-03-01 09:53 in General Discussion
Yup,

You think about the P/NP math issue before bedtime like I do - come on admit it. Do you think we will see a solution soon? I am working on it as an amateur math woman and its fun as long as you still get your sleep.

I admit that I am also obsessing over prime numbers for some reasons.

An example for those that wonder about me - the P/NP million dollar prize math problem

"A farmer wants to take 100 watermelons of different masses to the market. She needs to pack the watermelons into boxes. Each box can only hold 20 kilograms without breaking. The farmer needs to know if 10 boxes will be enough for her to carry all 100 watermelons to market."

Another example for the guys who like pictures.
MeDkj.png
eNbe7.png
Bhtsx.png
eNbe7.png
800 x 600 - 54K
MeDkj.png
800 x 600 - 46K
Bhtsx.png
800 x 600 - 38K

Comments

  • ercoerco Posts: 20,256
    edited 2014-02-26 10:41
    Sorry, I'm too fixated on a crossed ladders algorithm.

    Plus, I don't like watermelons. :)
  • ReachReach Posts: 107
    edited 2014-02-26 10:50
    Now that I think of it 8 queens is keeping me up late at nights too.
  • tonyp12tonyp12 Posts: 1,951
    edited 2014-02-26 10:56
    The Die Hard 2 riddle, how to exactly get 4gallons on the scale with only a 5gal and 3gal jug available? (unlimited water is available)
    diehard__3.pngdiehard__4.png
  • Hal AlbachHal Albach Posts: 747
    edited 2014-02-26 12:10
    Never saw the movie, but...

    1. fill 3 gal jug, pour into 5 gal jug
    2. fill 3 gal jug again, fill 5 gal jug from 3 gal jug. (3 gal jug now holds 1 gallon)
    3. empty 5 gal jug, transfer the 1 gallon from 3 gal jug to 5 gal jug.
    4. fill 3 gal jug and transfer to 5 gallon jug. 5 gal jug now holds 4 gallons
  • tonyp12tonyp12 Posts: 1,951
    edited 2014-02-26 12:44
    They don't really give away the answer in the movie as they rush the thought process through fast (good)
    Could also do it this way and is also correct.
    1. fill 5gal up, pour it in to the 3gal, you have 2 gallons left in it.
    2. empty 3gal, pour the other 2 gallons it to it.
    3. fill up the 5gal, pour another 1 gallon in to 3gal as to make it full.
    4. 5gal now have 4gallons.
  • ercoerco Posts: 20,256
    edited 2014-02-26 17:03
    All these puzzles are great fuel for problem-solving minds.

    But what if those 4 gallons were to refuel the jet on the treadmill?
  • mindrobotsmindrobots Posts: 6,506
    edited 2014-02-26 17:11
    erco wrote: »
    All these puzzles are great fuel for problem-solving minds.

    But what if those 4 gallons were to refuel the jet on the treadmill?

    You mean the one that took off or the one that couldn't?

    Quite honestly, once I get the bills paid, I sleep like a baby at night!
  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2014-02-26 17:15
    If the container isn't big enough I just use these ...
    Bungee.jpg
    ... Do I get my $1 million? ... Sorry that's the Oklahoma boy in me, gotta tie everything down. :-)
    Bungee.jpg
    600 x 447 - 107K
  • Cluso99Cluso99 Posts: 18,069
    edited 2014-02-26 19:58
    tonyp12 wrote: »
    The Die Hard 2 riddle, how to exactly get 4gallons on the scale with only a 5gal and 3gal jug available? (unlimited water is available)
    diehard__3.pngdiehard__4.png
    1. Fill 5 gal jug and pour into 3; leaves 2 in the 5 gal.
    2. Empty 3; Transfer 5 (2 gals) into 3 jug. (3 now has 2 gals)
    3. Refill 5; Transfer 1 gal from 5 into 3 (because 3 had 2 so accepts only 1) So 5 gal jug has 4 gals.
  • Cluso99Cluso99 Posts: 18,069
    edited 2014-02-26 20:06
    There is no solution possible because we do not know the individual weights nor the total weight of the watermelons ;)
    Its like the electric train travelling at 50mph northwest. The wind is blowing from the east at 25mph. In which direction is the trains' smoke blowing and at what speed?
    Reach wrote: »
    Yup,

    You think about the P/NP math issue before bedtime like I do - come on admit it. Do you think we will see a solution soon? I am working on it as an amateur math woman and its fun as long as you still get your sleep.

    I admit that I am also obsessing over prime numbers for some reasons.

    An example for those that wonder about me - the P/NP million dollar prize math problem

    "A farmer wants to take 100 watermelons of different masses to the market. She needs to pack the watermelons into boxes. Each box can only hold 20 kilograms without breaking. The farmer needs to know if 10 boxes will be enough for her to carry all 100 watermelons to market."

    Another example for the guys who like pictures.
    MeDkj.png
    eNbe7.png
    Bhtsx.png
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2014-02-26 20:23
    The water jugs "solution" suggests that the labelled capacities are met when they're filled to the top. But they're not. There's overage. So much for "exactly", to say nothing of suspension of disbelief.
  • ercoerco Posts: 20,256
    edited 2014-02-26 21:50
    On which side of the border were those plane crash survivors buried again?
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2014-02-26 22:09
    Hal Albach wrote: »
    Never saw the movie, but...

    1. fill 3 gal jug, pour into 5 gal jug
    2. fill 3 gal jug again, fill 5 gal jug from 3 gal jug. (3 gal jug now holds 1 gallon)
    3. empty 5 gal jug, transfer the 1 gallon from 3 gal jug to 5 gal jug.
    4. fill 3 gal jug and transfer to 5 gallon jug. 5 gal jug now holds 4 gallons

    Has something of the look and feel of the Tower of Hanoi puzzle...
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2014-02-27 04:47
    erco wrote: »
    On which side of the border were those plane crash survivors buried again?
    It's true they survived the crash but there was this one really keen erco wanting to bury them anyway, and he forgot which side of the border he buried them on too!
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2014-03-01 00:43
    Hmmm... getting back to the primes. They seem to have similar issues as the closest packing of spheres. It seems that spheres can fit into density of 12 or 13 as optimal, but the geometry shifts. Martin Gardner went on and on about this in the 1970s.

    If you really want to make some headway with maths, I suggest you read "17 Equations that changed the world" by Ian Stewart.

    He is brilliant. Rather than dwell on who was first and tedious proofs to finalize acceptance; he simply summarizes the players and the final outcome that brought about acceptance of new math concepts, the importance of the added knowledge, and how each item brings us forward to today's modern view. It all starts with a2 + b2 = c2; and moved ahead quite nicely. Much better than reading a history of mathematics that tries to cover all and everything and everybody that did what and when.

    Prime numbers, Platonic solids, Fibonacci series, the Golden Section and much more are interesting distractions. While a firm understanding of how pi and the natural log inter-relate is profoundly useful. And the use of complex numbers to model fluid dynamics, magnetics, and wing lift are very handy.

    Ian Stewart has the ability to pick out the thread of progress over several millennium, without getting bogged down in the curious.
  • Cluso99Cluso99 Posts: 18,069
    edited 2014-03-01 03:37
    Reach: Yes I do think about you at bedtime - rocking to sleep in your lovely boat on the water. I really miss that part - we have been back on land for about 4 years now :(
    We did spend a year cruising the east Australian coast (Sydney - Cairns including the Whitsundays ie the Great Barrier Reef) Thats ~1800nm each way.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2014-03-01 05:03
    Living and sleeping aboard a watercraft is indeed quite wonderful. Many many years ago, I lived in a house on a log raft on Schofield Creek, Reedsport, Oregon and loved it.

    Oddly enough, here is a photo of the house -- two bedrooms, kitchen, and living room.

    http://www.gettyimages.com/detail/photo/houseboat-on-schofield-creek-high-res-stock-photography/148932319

    I really have to wonder about the photo as I was told the house broke loose during a winter storm after a moved out and was last seem crossing the bar where the Umpqua River flows into the sea.

    I have a similar photo that I took, but no American flag flying.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2014-03-01 06:06
    Cluso99 wrote: »
    Thats ~1800nm each way.

    Do tell.
    Small world.
  • Cluso99Cluso99 Posts: 18,069
    edited 2014-03-01 07:12
    Australia is about the size of the USA -about the same across and length. So I guess its about Miami to NY.

    I have all the details on my website www.bluemagic.biz
  • Cluso99Cluso99 Posts: 18,069
    edited 2014-03-01 07:19
    Loopy - looks nice - shame if thats what happened to it.

    After you haved livd on board for some time its hard to sleep on land. When weput the boat on the hardstand for antifouling, we slept onboard overnight. Terriblenights sleep - felt like theboat was rocking all night!
  • PublisonPublison Posts: 12,366
    edited 2014-03-01 07:32
    Cluso99 wrote: »
    Australia is about the size of the USA -about the same across and length. So I guess its about Miami to NY.

    I have all the details on my website www.bluemagic.biz

    I think PJ was making a funny as nm, (Nautical Miles), looks like nano meters.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2014-03-01 08:24
    http://en.wikipedia.org/wiki/Nautical_mile
  • User NameUser Name Posts: 1,451
    edited 2014-03-01 09:53
    Loopy Byteloose wrote: »
    Many many years ago, I lived in a house on a log raft on Schofield Creek, Reedsport, Oregon...

    That you once lived in a place like that, and now live in a Kaohsiung warren, is blowing my mind!! Hard to imagine a greater contrast.

    FWIW, I once lived on a sailboat in Mission Bay (San Diego). Loved it! It was a sad day when I sold the boat and moved inland. But family life has been ample compensation. :)
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