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 [quote="Ghost Post"]Lawrence of Puzzlania When I first read the Lawrence of Puzzlania puzzle, I thought just as everyone else did. However after close inspection, several holes in the logic of the "ANSWER" appeared. I have listed these below. If anyone finds any problems with my logic or reasoning, please feel free to post and let me know. #1. The puzzle states… "…no part of the desert is more than a hundred miles in any direction from civilization." Rearranging the sentence might help it become clearer. In any direction from civilization, no part of the desert is more than a hundred miles. [away]. "Civilization" is not outside of the desert, but rather in the middle. #2. The next problem is that Lawrence is LOST! Many of the posted solutions, and even the "official" solution(s) seemed to think that being lost, means that you know where you are. The first "official" solution assumes that the oasis is in the center of the desert. That information is not given, and in no way can it be presumed to be true. Remember, Good'ol Lawrence has no Idea where he is. #2-b This solution goes on to say that to get out of the desert in the fastest amount of time. Lawrence must run out of food and water just as he exits the desert. This would logically put him 60 miles from the edge of the desert. However, last time I checked, a compass does not measure long range distances. Lawrence would have to start at the edge of the desert and walk into it, to accurately find a place 60 miles inside of the desert. Although, if he were at the edge of the desert, he wouldn't be in this situation. The solution continues to work its way BACKWARD from there. #3 I mentioned earlier, in "#1", that the "civilization" had to be in the middle of the desert. This is not entirely correct howsoever. "civilization", would only HAVE to be in the middle if the desert was round and had a radius of 100 miles. In truth, the size and shape of the desert were not specified. The "civilization", in a smaller desert, could be anywhere inside, and still conform to the "rules" #3-b My last main [nit-picky] point is that the size or number of "civilization" are never given. Picture in your mind a city surrounded by a desert with a 100-mile radius. Now place a similar city and desert next to the first, overlapping the deserts. And then a third city and desert overlapping the second……….etc. This "simulation" gives a new view to the puzzle that was previously not explored. I believe that the puzzle is not possible to solve accurately with the information given. Thank you for reading my thoughts on the issue of this puzzle. I look forward to reading follow-up posts, and responding to them. Have a Puzzlania day. Raven [/quote]
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tv snake
Posted: Sat Dec 16, 2000 10:02 am    Post subject: 1

Does "any direction" include up or down?
Wonko the Sane
Posted: Fri Dec 15, 2000 2:02 pm    Post subject: 0

Wow...mathgrant is ticked
mathgrant
Posted: Thu Dec 07, 2000 1:48 am    Post subject: -1

Everybody: I thought we were finished with that by now! I thought we now cared about the new stuff like the potpourri puzzle. Why can't you just concentrate on trying to get that donation through? Then you can get back to trivial stuff like this.

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[This message is being edited by mathgrant (being edited right now).]
Andy
Posted: Thu Dec 07, 2000 12:57 am    Post subject: -2

Raven,

(1) "Fortunately, you know that no part of the desert is more than a hundred miles in any direction from civilization."
Most people seem to interpret this as meaning, "From any part of the desert, civilization is no more than a hundred miles away in any direction." As you point out, that isn't exactly what the puzzle says. But what does it say?
Civilization isn't a point - it may be considered an amorphous blob for this discussion. In this case, "distance from civilization" is usually taken to mean "minimum distance from any point of civilization" or "distance from the nearest point of civilization." With this understanding, we can restate "no part of the desert is more than a hundred miles in any direction from civilization" as "to any part of the desert, for any direction, there is some point in civilization from which the distance is no more than a hundred miles." Now, if we accept the axiom that the distance from A to B is the same as the distance from B to A, the conclusion is that the desert must be surrounded entirely by civilization - and the desert fits into (but does not necessarily fill) a circle 100 miles in diameter whose entire circumference is touched by civilization.

(2) The "official" solutions do not assume that the oasis is in the middle of the desert - just that it is somewhere in the desert, and that Lawrence can reach civilization by traveling no more that a hundred miles in any direction (the same direction for the entire hundred miles).

(2-b) The solution seems to assume worst-case throughout. If the worst case does not actually happen, camp Alpha will be less than 60 miles from the edge and Lawrence will have food and water remaining when he reaches the edge. This of course will mean that he carried more food and water to camp Alpha than he really needed, and didn't escape in the minimum time - but the puzzle doesn't ask for the minimum time, it asks for the minimum guaranteed time - and the non-worst-case escape will be within the guaranteed time.

(3) If civilization were in the middle of the desert, then a desert point south of civilization would not be "no more than a hundred miles north" from civilization.

(3-b) See (1) above; civilization must completely surround the desert. Its thickness cannot be deduced (e.g. a highway or even a fence adjacent to the edge of the desert might qualify). There is thus no assurance that reaching civilization will guarantee survival - but the objective is just to reach civilization; survival beyond that is not specified.

[This message has been edited by Andy (edited 12-06-2000).]
knightofni
Posted: Sun Dec 03, 2000 5:43 pm    Post subject: -3

I read your posts, and they are incorrect. Simply restating the rule doesn't make it logically equivalent to the original. Basically, what the rule states is that if he could carry 100 miles worth of food, he could guarantee escape by walking in any direction. Your rewording of the rules is incorrect.
mithrandir
Posted: Sun Dec 03, 2000 3:54 am    Post subject: -4

what if Lawrence is really on Dune? maybe a planet that has a radius of 100/pi miles, with one point of civilization? what are the odds of him finding it then?

[This message has been edited by mithrandir (edited 12-02-2000).]
Ghost Post
Posted: Sun Dec 03, 2000 2:58 am    Post subject: -5

so if you have civilization. Travel in any direction from it, and no part of the desert will be beyond 100 miles. That doesn't disprove me at all!

Did you read ANY of my postes?????

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He who laughs last, thinks slowest.
knightofni
Posted: Sun Dec 03, 2000 2:23 am    Post subject: -6

The reason the answer IS correct to Lawrence of Puzzlania is because the question says that "no part of the desert is more than a hundred miles in any direction from civilization." If the desert were to be surrounding civilization, and you went the wrong way, you obviously would not reach civilization ever...
Ghost Post
Posted: Sun Dec 03, 2000 2:17 am    Post subject: -7

I don't mean to get pushey, but no one has proved me wrong. Can't anyone else see my logic????

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He who laughs last, thinks slowest.
Ghost Post
Posted: Sat Nov 25, 2000 11:39 pm    Post subject: -8

Finally! some descussion!

I am not sure who's idea tv snake is advocating. but he once again brings up my point. If the oasis is a little off center. How can you GARENTEE (sp?) that Lawrence will get out in that few of days? If the oasis is, say, half the radious to the edge, Lawrence COULD walk out much faster, but you can't GARENTEE which way is the shortest distance. He could walk the long way and take much longer, if he decides that this way is over 100 miles, and turns around, and walks the other way. He has wasted alot of days. The answer is still wrong.

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He who laughs last, thinks slowest.
tv snake
Posted: Sat Nov 25, 2000 4:50 am    Post subject: -9

That's a good point though... the fact that the oasis is in the middle of the desert is actually the best scenario. If the oasis was on the edge of the desert and you walked into the centre, you'd have to cover 200 miles...

The other method (desert really has 100 mile diameter, go 30 miles then 70 the other direction) does prevent you from being stupid and walking away from the edge.
Ziggy
Posted: Fri Nov 24, 2000 2:40 pm    Post subject: -10

Here's the thing, we don't know where the edge of the desert is. But by setting up Camp Delta as stated in the original solution, Camp Delta is at MOST a set distance away from the edge. The same goes for Camps Beta and Alpha.

The thing is, they were going for the worst case scenario. This gets us out in the worst case in 11.75 days. We will get out of the desert faster if it is not the worst case, but that's not what the puzzle was.
Ghost Post
Posted: Thu Nov 23, 2000 1:55 am    Post subject: -11

I understand that I did get a little to technical on you guys. I can accept that. But I still say that the offical solution is wrong. Look at #2 and #2-b. The offical solution assumes to much. It assumes the oasis is in the middle of the desert, but we don't know this, because it says Lawrence is lost and doesn't know where he is. If he know that the oasis is in the middle, he is not lost at all. The other thing, is that the answer works backwards from 60 miles from the edge, how do we know where 60 miles from the edge is?? I am sorry if I am getting anoying, and I dont mean to rip the entire puzzle appart. I appreciate the time and effort it takes to keep a great site like this going.

Raven
HyToFry
Posted: Wed Nov 22, 2000 10:23 pm    Post subject: -12

your logic is that the puzzle has to be real life, we get this here often.

the logic does not have to be real life. if kevin says the sand is blue, it's blue, if he says that civilisation is no more than 100 miles, it's no more than 100 miles. he is a god of the puzzles. your correct that civilization is no more than 100 miles, which means it could be 2 miles south of you. but we want a garentee that we will make it out, not a might maybe make it out.
Ghost Post
Posted: Wed Nov 22, 2000 8:51 pm    Post subject: -13

*sigh* ...ok....my bad.... The etiquitte of the forum is still new to me.

[This message has been edited by Raven (edited 11-22-2000).]
hank
Posted: Wed Nov 22, 2000 8:45 pm    Post subject: -14

Raven, if you have an other solution, please lets have it. Post it on the thread where you read all the other solutions. Many of us have forgotten the details of the puzzle, and are not about to search back to bone up.
Ghost Post
Posted: Tue Nov 21, 2000 2:15 pm    Post subject: -15

I can see where you are comming from, but I still disagree. The puzzle says that no part of the desert is MORE THAN a hundred miles FROM civilization. First the puzzle says FROM, therefor, civilization in the point at which in any direction from it, there is desert. Secondly, The puzzle says MORE THAN a hundred miles, so all, or part of the desert could be LESS THAN a hundred miles away. (remember, the desert doesn't have to be round.) [Their answers don't work, they cheet. In addition, what sounds stranger, a city in a desert, or a desert with a round city that serounds the desert?]lol
Raven

[This message has been edited by Raven (edited 11-21-2000).]

[This message has been edited by Raven (edited 11-21-2000).]
Logain
Posted: Tue Nov 21, 2000 6:04 am    Post subject: -16

The problem is that as stated, the desert is meant to be a circle with civilization around it in all directions. ( this isn't a post-apocolyptic town lost in the middle of a vast desert )

The statement that no part of the desert is greater than 100 miles means the diameter of the desert is 100 miles. So if you were blindfolded and put on the edge of civilization, you could walk in any direction 100 miles and be guaranteed to make it out.
Ghost Post
Posted: Tue Nov 21, 2000 5:13 am    Post subject: -17

Lawrence of Puzzlania

When I first read the Lawrence of Puzzlania puzzle, I thought just as everyone else did. However after close inspection, several holes in the logic of the "ANSWER" appeared. I have listed these below. If anyone finds any problems with my logic or reasoning, please feel free to post and let me know.

#1. The puzzle states… "…no part of the desert is more than a hundred miles in any direction from civilization." Rearranging the sentence might help it become clearer. In any direction from civilization, no part of the desert is more than a hundred miles. [away]. "Civilization" is not outside of the desert, but rather in the middle.

#2. The next problem is that Lawrence is LOST! Many of the posted solutions, and even the "official" solution(s) seemed to think that being lost, means that you know where you are. The first "official" solution assumes that the oasis is in the center of the desert. That information is not given, and in no way can it be presumed to be true. Remember, Good'ol Lawrence has no Idea where he is.

#2-b This solution goes on to say that to get out of the desert in the fastest amount of time. Lawrence must run out of food and water just as he exits the desert. This would logically put him 60 miles from the edge of the desert. However, last time I checked, a compass does not measure long range distances. Lawrence would have to start at the edge of the desert and walk into it, to accurately find a place 60 miles inside of the desert. Although, if he were at the edge of the desert, he wouldn't be in this situation. The solution continues to work its way BACKWARD from there.

#3 I mentioned earlier, in "#1", that the "civilization" had to be in the middle of the desert. This is not entirely correct howsoever. "civilization", would only HAVE to be in the middle if the desert was round and had a radius of 100 miles. In truth, the size and shape of the desert were not specified. The "civilization", in a smaller desert, could be anywhere inside, and still conform to the "rules"

#3-b My last main [nit-picky] point is that the size or number of "civilization" are never given. Picture in your mind a city surrounded by a desert with a 100-mile radius. Now place a similar city and desert next to the first, overlapping the deserts. And then a third city and desert overlapping the second……….etc. This "simulation" gives a new view to the puzzle that was previously not explored.

I believe that the puzzle is not possible to solve accurately with the information given. Thank you for reading my thoughts on the issue of this puzzle. I look forward to reading follow-up posts, and responding to them. Have a Puzzlania day.

Raven