Find solution
How to help the earth?! HELP?

I need Math People to help me find out how long it takes 2 Last (Wo)Men on Earth to meet.

  • How long should it reasonably take before 2 "Last Men on Earth" meet? I'm writing a story about a post-apocalyptic mathematician, something to do with zombies. Any such character would naturally be inclined to work the following problem in such a situation. My difficulty lies in myself having very few mathematical skills (2 +2 is four, heh heh heh, me smart). So, Hive Mind, assist me! Question: Assuming that there has been a global catastrophe of Hollywood proportions and most of the human race has died off (or become zombies, etc), and assuming that any lone survivors will, eventually, come to think of themselves as the "Last (Wo)Man on Earth" in the Richard Matheson vein, and assuming a slow rate of travel among these LMOE, how long will it take before 2 LMOE meet, and how many LMOE are there on Earth in total? Assumption 1: Most of the human race has died off. Let's assume that 99.99% of the global human population is gone, just so we have something to work with. Assumption 2: Lone survivors come to believe themselves as the Last Man on Earth. Let's assume that it takes 3 months of being alone to come to this assumption. This assumption is contingent on not seeing another -living- human being during this time, so we can expect city dwellers to have a margin of error here leading them to come to this conclusion later than their rural or islander counterparts, being as there should (at first) be more survivors in cities. However, they can't be considered LMOE unless they end of alone, so it may take some time for their fellow survivors to die off and thus the margin of error. If their fellow survivors never die off, they can't be considered LMOE. Let's say any group of survivors has a half-life of 1 week, and no group can begin with more than 8 survivors. Assumption 3: A slow rate of travel among the LMOE. Let's say, for the sake of the problem, that half the LMOE are home-based and half are travel-based. Home-based LMOE stay within their little "fortified zone" of about 5 square miles (gathering supplies, killing zombies, and waiting out the storm going slowly insane). Travel-Based LMOE move slowly (at about 5 miles per day) due to travel hazards such as zombie hordes, traffic blocks, fires, etc. They're determined to find other survivors and thus keep themselves from madness. Hidden Assumption 4: The game begins on Day 0. Day 0 is the day when the travel-based LMOE begin moving, the home-based LMOE start gathering supplies, and city-based groups of survivors begin dying off down to single LMOE. How many days will it take before any 2 LMOE meet? I realize I am not a mathematician (I am in fact, and English major and the opposite of a mathematician), and so any data that needs to be filled in, altered, or deleted should be in order for the problem to be solved. Cheers.

  • Answer:

    I feel like there's a very specific question in here. Kind of like the scene in Cast Away where Tom Hanks does some quick calculations to figure out the search area his rescuers would have to cover, and realizes: "that's twice the size of Texas". Your problem only works if the LMOE is alone in a rural (or semi-rural) area. Like, perhaps a small town, 8 hours drive from anything else. A big city is the natural destination for survivors and a rational person looking for others would come up with beacons or something. But forget about that for now. Let's assume your narrator is the only survivor in a region of 100,000 people; assuming similar death rates, perhaps there are 3000 people in the US or so. Suppose they are evenly distributed across the US land area (not realistic though - most of them would be in major cities). The US is about 3.5 million sq miles (land area) which means each person is alone is an area of about a thousand square miles. Hmm... I could go through a calculation but there's no point. The result is hugely sensitive to how the populations are distributed, not to mention initial survivor estimates, and a whole lot of other factors. Your mathematician would realize such a calculation is meaningless with so much uncertainty. It could range from hours to years.

mr_book at Ask.Metafilter.Com Visit the source

Was this solution helpful to you?

Other answers

James Surowiecki writes about 23skidoo's technique in Wisdom of the Crowds. There have been experiments where people were told "you're supposed to meet someone in New York, but you don't know the time nor the place. Where would you be at which time?", and a good part of the people gave the same answer (noon at Central Station, I think). So yes, the people wouldn't move randomly at all in a realistic scenario.

dhoe

kill as many people as necessary to make the problem work.

mr_book

How exactly would shortwave radio be restricted? We're talking mathematician here, shortwave is a hardware problem. The smart mathematician would stay put. He or she would announce his or her presence with authority by blowing shit up and making a big fire in the sky. Also smoke. Then he or she would start a search algorithm. The search vector itself would be very interesting. Can he or she somehow tag zombies like sperm whales and release them back into the wild? Somehow the tags could lead back to him or her? Maybe the tagged zombies could pass this condition on to zombies they meet along the way? That'd be awesome, exploit the fuckers instead of bashing their heads in.

stubby phillips

Metafilter: kill as many people as necessary to make the problem work.

dersins

kaibutsu: Referring to the original question, I used .01%, not .01 in my response.

wigglin

kaibutsu: .01 * 6B is 1%. You need .0001 * 6B, which is two orders of magnitude smaller. To me, the biggest variable here is Smart Zombies vs. Dumb Zombies. If the zombies are the groaning, knuckle-dragging type, than it seems reasonable to me that the vast majority of people would leave trail markings of where they went, signs and beacons miles in every direction, any sort of thing to comfort them that IF there is someone else, we won't just be two ships passing in the night. Smart zombies which could follow these markings/beacons, would, obviously, make this a bad idea, and greatly diminish the odds of success.

paisley henosis

wigglin - .01 *(6 billion) = 60 million. If we're America-centric, it's worth noting that 350 million -> 3.5 million. iconjack - ah, but would you wait there if that's where the zombies (on some weird primal instinct) were going, too? More generally, if everyone has reason to hide and not broadcast their existence, the survivors will be less likely to find one another. If I were a survivor in hiding, I would probably try to think of an isolated area in which hunter-gathering would be relatively easy. Probably not Appalachia, to avoid the Lovecraftian horrors known to inhabit those parts; but maybe someplace like the pacific northwest, where winters are relatively mild, population not terribly dense, and wild life is rampant. Nothing coastal; too many 'people' around, though the Lost Coast in Northern California might fit the bill.

kaibutsu

I'd wait by the pig in Seattle's Pike Place Market.

iconjack

Stuart_s said: .01% survival would reduce the population to a level roughly in line with that of the mid-18th century. This is not correct. If .01% survival is ~650,000, this would be lower than the estimated population in http://www.census.gov/ipc/www/worldhis.html. You must have calculated 10% survival rate. As for the original question, it seems unanswerable with the given information. We would need to know what it is that is killing everyone off, how the "disease" spreads, the population densities of the particular areas these LMOE are in, and so on. Assuming a completely equal rate of death spread over the planet, if the survivors are in Manhattan, they would find each other relatively quickly. If they are in Mongolia, it's plausible they would never find each other. How would your fictional mathematician know that precisely 99.99% has died off? You as the author know this, but this variable is not known to him. He wouldn't bother trying to do this calculation.

wigglin

Load more

Related Q & A:

Just Added Q & A:

Find solution

For every problem there is a solution! Proved by Solucija.

  • Got an issue and looking for advice?

  • Ask Solucija to search every corner of the Web for help.

  • Get workable solutions and helpful tips in a moment.

Just ask Solucija about an issue you face and immediately get a list of ready solutions, answers and tips from other Internet users. We always provide the most suitable and complete answer to your question at the top, along with a few good alternatives below.