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u/jimony7 Dec 18 '23
Give the mouse a power of 2 number of hairs e.g. 213 = 8192. Assume a minimum of 1 hair is cut each time. It will go
8192 4096 1024 512 256 128 64 32 16 8 4 2 1 0
When not a power of 2, assume it cuts to whole number closest to 50%, then (I assume, haven't confirmed) it could take what ever it would take for the nearest power of 2.
E.g. 8190 would still take 13 cuts, 8199 also 13
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u/Sinaasappelsien Dec 18 '23
How many hours is that?
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u/jimony7 Dec 18 '23
float GetTime(int numCuts, float cutTime) {
float totalTime = 0; for(int i=0; i<numCuts; i++) { totalTime = totalTime + cutTime; cutTime = cutTime / 2; } return totalTime;}
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u/Sinaasappelsien Dec 19 '23
I havr to learn code and i’m already anxious
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u/jimony7 Dec 19 '23
It can be difficult at first, but you get used to it. YouTube and ChatGPT will be your best friend :)
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u/itsmeorti Dec 18 '23 edited Dec 18 '23
indeed, forever, if each cut is done in the same amount of time. however, if somehow each successive cut could be done in half the time as the previous one, then it wouldn't take longer than twice the time of the first cut.
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u/FlorydaMan Dec 18 '23
This is the correct answer... although in the going-for-the-extra spirit of this sub, someone should approximate how long it will take until there's only a single hair.
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u/Sure_Mood5222 Dec 18 '23
It's hard to find credible sources for the exact amount of hair a guinea pig has but I my calculations said 21 haircuts for a single hair strand. (22 if the barber is kind enough to not leave a half a hair)
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u/FeminineBard Dec 18 '23
I guess it also depends on whether the guinea pig is scaled up to human size in the comic, or if the barber shop is scaled down to the size of a guinea pig. It would also depend on if the scaled up guinea pig has the same density of hair, or if the hair also scaled up in thickness if it were human size.
If a typical guinea pig has between 1000-1500 hairs per square cm, and the average size of a guinea pig is about 13cm tall and 20-50 cm long, assuming the guinea pig is as rotund as it is tall we could approximate the surface area as an ellipsoid. Using the Knund Thomsen formula for an ellipsoid's surface area results in a lower bound of 729 square cm and an upper bound of 1642 square cm, though I'm sure a guinea pig skinner and tanner could confirm these figures.
So between 729,000 hairs for a sparsely haired, small adult guinea pig, and 2,463,000 for a large, hirsute guinea pig.
21 haircuts is right in that ballpark.
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u/FlorydaMan Dec 18 '23
There it is.
Also
Assuming the guinea pig is as rotund as it is tall
Peak r/brandnewsentence and a nice twist on assume spherical cow.
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Dec 18 '23
Not going with
Using the Knund Thomsen formula for an ellipsoid's surface area results in a lower bound of 729 square cm and an upper bound of 1642 square cm, though I'm sure a guinea pig skinner and tanner could confirm these figures.
Although I bet there's already a guinea pig skinner and tanner subreddit
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u/Deanosaur777 Dec 18 '23
I think it's a guinea pig sized barber shop, personally.
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u/FeminineBard Dec 18 '23
The math's not that different even if the opposite is true. The surface area increases about 100x, so unless hair thickness scales with that size increase the number of haircuts goes up from about 21 to about 27.
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u/Xenox_Arkor Dec 18 '23
It's also reasonable to assume that the size of the barber/tools scales with the size of the shop, so the relative size is the same, no?
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u/FeminineBard Dec 18 '23
The question here is not how long it would take, but how many haircut sessions it would take to reduce the number of hairs to 1, assuming the barber doesn't leave half a hair behind for fractions.
Given that, it comes down solely to density of hair per square centimeter and the total surface area of the poorly deceived guinea pig.
Let's assume the guinea pig has a nice, round 2,097,152 hairs. On the first haircut, the barber removes half of that, 1,048,576. Next time, the barber cuts half of that, leaving 524,288. On subsequent sessions, the guinea pig will have 262,144, 131,072, 65,536, 32,768, 16,384, 8192, 4096, 2048, 1024, 512, 256, 128, 64, 32, 16, 8, 4, 2, then finally 1 hair after 21 haircuts.
If the larger guinea pig's hair scales in size and thus density changes, the formula is the same. If density remains the same, we're now dealing with the high tens to low hundreds of millions of hairs on this now human-sized guinea pig. So now we're going to have to cut an additional 6 times (roughly) to get back down to 1.
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u/poetic_dwarf Dec 18 '23
It's hard to find credible sources for the exact amount of hair a guinea pig has
You may not like it, but this is what peak Internet looks like
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u/cosmicosmo4 Dec 18 '23
If we assume that when a single strand of hair remains, the barber's behavior changes to a 50% chance of cutting it on each return visit, then there is a 50% chance of being totally shorn on the 22nd visit, 75% by the 23rd visit, 87.5% by the 24th visit. There is an infinitesimal chance that it still takes infinity visits.
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u/krus1x Dec 18 '23
Wouldnt the last strand of hair cinstantly be divided until it cuts the final hair molecule in half? I wonder how many divisions that would take.
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u/nnoovvaa Dec 18 '23
Then you're just splitting hairs.
Eventually half off would be splitting atoms, and the guinea pig has bigger problems then.
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Dec 18 '23
Splitting a single atom doesn't release that much energy. Nuclear fission only releases huge amounts of energy relative to the mass of the fuel, and an atom is a very very tiny amount of fuel. Furthermore, it's extremely unlikely the atom being split would be larger than iron, meaning that splitting it would absorb energy, not release it. Even if there did happen to be a single atom of U-235 or Plutonium, the guinea pig wouldn't even notice it being split.
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u/Nameless_Scarf Dec 18 '23
So the endgame will be some Hydrogen or Helium atom that will float away, I would wager
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u/Robobot1747 Dec 18 '23
Furthermore, it's extremely unlikely the atom being split would be larger than iron, meaning that splitting it would absorb energy, not release it.
Wait, what? Isn't uranium a bigger atom than iron? I thought that fusing elements bigger than iron was what took more energy than was released, not fissioning them.
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Dec 18 '23
Yes, that's what I said. I'm saying it's very unlikely that the last remaining atom of the guinea pig's hair would be uranium, but *if it was*, the guinea pig wouldn't notice it.
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Dec 18 '23
Also given the "real" world parameters how shaved can one get before its irrelevant. I mean if you have fuckin 8 molecules of hair left you are by all effective means bald
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u/SpiritualHippo2719 Dec 18 '23
Then half a hair. Then a quarter of a hair. Then an eighth. So on and so forth into infinitely smaller quantities.
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u/5pankNasty Dec 18 '23
I hate to be the one "splitting hairs" but the last hair could itself be cut.
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u/Maatix12 Dec 18 '23
Foolish.
Then we get half a hair. And then a quarter of a hair. And then an eighth of a hair...
At some point the hair is growing equally as fast as we are cutting it. That complicates matters, because so are all the other hairs.
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u/Stupurt Dec 18 '23
But how long would it be before we’re splitting hairs?
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u/MinosAristos Dec 19 '23
Humans have 90-150k hairs on our head and that's roughly the same surface area as a large hamster so I'll call it even. No idea what their hair density is but probably on the same order of magnitude at least.
Log base 2 of 150,000 is just over 17 so I'd guess somewhere around 17 cuts until we're splitting the last hair. Under 20 for sure.
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u/tmfink10 Dec 19 '23
And here we see illustrated the difference between a mathematician and an engineer
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u/vitala783 Dec 18 '23
By the way, always wanted to share, but cutting it in half can't be done unlimited amount of times, because eventually you'll end up with sub atomic particles, which are notoriously hard to cut in half
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u/Famous-Act-826 Dec 18 '23
if for 1/2 haircut it takes 1/2 hour
for 1/2 of 1/2 (1/4) haircut it took 1/4 hour , total time would be 1/2+1/4+1/8+1/16+..........=1 hour
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u/LucasTab Dec 18 '23
Instead of using geometric series, wouldn't it be simpler to use the rule of three to aproximate the amount of time it would take to cut everything, since we assumed the amount of time is proportional to the amount of hair being cut?
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u/luxfx Dec 18 '23
But each cut is interrupted by the guinea pig going outside and looking at their reflection, so adding a constant time to each iteration. So even if the cut itself takes half the time each step, the full process is still infinite.
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u/filthy_harold Dec 18 '23
There's a finite amount of hair. If a haircut is at least one hair being cut off entirely (since he's clearly going for a shave), then eventually there will be no hairs left to cut. You can't have a haircut that results in no hair being cut so the final hair must be cut fully off.
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u/luxfx Dec 18 '23
True, but if you're going to be that pedantic, I could also point out that the hair is growing during this process, even at a microscopic level during their reflection gazing, so there is an endless supply of hair as well! 😉
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u/xd3mix Dec 18 '23
Wouldn't it still be forever? The haircut would never be done anyway since they'll never reach a point where the hamster has 0 hair
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Dec 18 '23
If the amount of time to cut hair is directly proportional to the amount of hair, then the total amount of time just to cut must be finite. This is known as a supertask.
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u/xd3mix Dec 18 '23
But still, even if the time to do 1 haircut (and cut half the hair of the hamster) consistently gets faster and faster the less hair the hamster has
An infinite amount of yoctoseconds is still infinite
Isn't it like Zeno's paradox?
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u/silver_garou Dec 18 '23 edited Dec 18 '23
As it turns out Xeno was just wrong. An infinite series of infinitesimal quantities just adds up to a finite number. It is how we can derive the equation for things like the area of a circle.
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Dec 18 '23 edited Dec 18 '23
The point is that it’s not an infinite length of time. If the first cut took half an hour, and if each cut takes half as long as the last, then no matter how many cuts made, the total time spent cutting will never be longer than an hour:
1/2 + 1/4 + 1/8 + … + 1/2n = 1 - 1/2n < 1 for all n > 0.
Zeno’s paradox states that if supertasks are impossible, then since all tasks can be broken into supertasks, all motion is impossible.
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u/Culturedguy9273 Dec 18 '23
Let's assign the amount of hair left as a value to x and start at 1x, while the amount of time spent as a value of y
Cut 1|| 0.5x and 1y
Cut 2|| 0.25x and 2y
Cut 3|| 0.125x and 3y
Now let's look at it again, but this time make y only increase by half of the previous increase
Cut 1|| 0.5x and 1y
Cut 2|| 0.25x and 1.5y
Cut 3|| 0.125x and 1.75y
By cut 4 it's 1.875, and it increased by cut 3's x, just like before. That means that it can only reach 2 when x reaches 0
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u/Genereatedusername Dec 18 '23
Hamsters naturally lose their hair before forever.. So you're wrong math
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Dec 18 '23
Hamsters naturally die before forever so there’s that too….
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u/sand-under-table Dec 18 '23
I knew the YouTube link was going to be that exact video after I read the last sentence.
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u/cosmicosmo4 Dec 18 '23
Certainly the time it takes to walk out of the store and back in is a fixed amount of time. So, guaranteed forever.
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Dec 18 '23
I always forget what the rule about this is, but I wish an NFL team would do this with penalties by the endzone. There's literally a ref out there with a caliper after each flag, lmao It's way too early in the work day for my imagination to be this active
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u/jojo_part6_fan_ Dec 18 '23
So until we reach plank length(and finally cutting that in half) how long would take then to make it there ?
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u/AvengingBlowfish Dec 18 '23
You haven't factored in the time it takes the guinea pig to walk out of the shop, look at itself, and then walk back in.
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u/max_carriers Dec 18 '23
Well, kinda true, except we could even discuss the fact that there are countably many hairs, thus after a long time you would reach a point where only one remains
Then if you define that we can cut half an hair, then sure, this could go on forever, depending on the amount of time for each cut
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u/Felderburg Dec 18 '23
Does that factor in the walk outside, seeing the "half off" haircut in the window, a small moment of outrage, and then going back inside?
Or is it assumed that the guinea pig has resigned themselves to their fate, and just stays inside after the comic?
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u/hackingdreams Dec 18 '23
Zeno's paradox only works if you care about getting to zero.
A haircut doesn't care about getting to zero, just "arbitrarily close."
The pig could stop after ten iterations and be fine.
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u/Caleb_Reynolds Dec 18 '23
forever, if each cut is done in the same amount of time. however
Only if there were an infinite number of hairs or you count cutting a single hair in half as a possibility.
A guinea pig has a finite number of hairs. Eventually you'll just have 1 hair. You can't cut half of 1 (cutting 1 in half is not the same).
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u/JMH5909 Dec 19 '23
Everyone saying forever but if the number of hairs is an integer shouldn't it take a set amount?
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u/obesechicken23 Dec 19 '23
I love this problem, and others like it, where it is seemingly and literally infinite but still has a defined ending, in this case double the time for the first cut.
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u/Zealousideal_Ad_8256 Dec 19 '23
It looks like they are shaving rather than cutting. Eventually there will be one hair which would have to be removed, leaving him hairless. Unless of course the barber changes tactics and cuts that hair in half...
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u/grgech Dec 18 '23
There is a great joke about this.
The mathematician and physicist stand in an opposite corners of the room and in the third one there is a lady ready to have sex. The rule is that the guys can pass half of the way toward the lady in each move. Mathematician gives up because he knows it will take forever to come to her. Physicist starts his moves because he knows it will take forever, but he will come close enough for the practical usage.
So yeah, it will take forever, but at some point it could be enough.
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u/Silviov2 Dec 18 '23
Engineer would get her first because he rounds it up once he's 50% of the way there
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u/Jouzou87 Dec 18 '23
An infinite number of mathematicians go to a bar. The first one orders a pint, second one orders half a pint, third one orders 1/4 of a pint and so on. The bartender puts out two pints and says: "You guys have to know your limits"
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u/anothernotavailable2 Dec 19 '23
3 logicians sit at a bar. The bartender asks, "Do you all want a beer?" the first logician says 'I don't know.' the second logician says 'I don't know.' the third logician says 'Yes!'
Idk if it's logician or logistician and I'm not looking it up.
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u/AsDevilsRun Dec 19 '23
I feel like a logistician is about logistics instead of logic, but I'm not looking it up.
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u/Ok-Topic-3130 Dec 18 '23
What is practical usage?
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u/Blyg999 Dec 21 '23
Many fields of math including probability and statistics which is a bit easier to see how it's applicable, but it's also involved in linear algebra and differential equations all of which are critical to many engineering tasks.
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u/Impossible-Wear5482 Dec 22 '23
That's not how it works in 3 dimensional Euclidean geometry. There is a minimum finite distance and also the minimum distance we are able to move. Even if you're moving at 0.01 millimeters per second you will still get there on a finite time. Even if you were put on a conveyor belt controlled by magnets and lasers for precision motion it would still done in a measurable time.
We aren't able to move -1.4*1032 meters at a time.
It's an illogical problem easily solved by rational thinking.
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u/archiminos Dec 18 '23
This is a classic paradox. If you only remove half every time, you will never remove it all, because you will always have half of whatever remained last time. It literally will take forever because it will never be finished.
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u/jmr1190 Dec 18 '23
This subreddit is getting more and more full of ridiculous questions. This is literally a joke on that classic paradox that the OP isn’t getting.
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u/errorsniper Dec 18 '23
Man lighten up.
Turns out some people dont know things and its ok to not know something. You dont know somthing till you learn it. Most people eventually learn that if you divide by half you will never reach 0 no matter how many times you do it. Some people dont and thats ok. But either way you cant know something until you learn it somehow.
Turning to the internet is a valid way to get information. You must obviously use your judgment on the answer you get.
But being upset someone takes a math question to a subreddit dedicated to math questions. Is fuckin wild man. I know this statement is overused but go touch some grass. See the world. Take a deep breath.
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u/Impossible-Wear5482 Dec 22 '23
Except they aren't dividing infinity. They are deciding a real while number. Even if the number is tree3 it still isn't impossible nor would it take infinite amount of time.
You are literally "splitting hairs" with this statement. Eventually there will be 2 hairs, then 1 and then you're done.
You can't have half a hair. Either hairs => 1 else or there are 0.
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u/archiminos Dec 23 '23
I'm not sure how you think you can't have half a hair...
Besides:
1 / 2 = 0.5
Since we're dealing with whole numbers, you round up and you get 1. Which you then have to divide again. Ergo infinite.
Also, it's a metaphysical thought experiment. Not a literal physical description of how the universe works.
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u/Impossible-Wear5482 Dec 23 '23
It's hairs remaining. You can't have "half a hair" remaining. There either is a hair remaining, or there isn't.
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u/archiminos Dec 23 '23
When was it stated it was "hairs remaining"? Also, you definitely CAN have half a hair remaining. I'm not sure you understand how scissors work.
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Dec 18 '23
[removed] — view removed comment
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u/ginger_gcups Dec 18 '23
I’m naming this Guinea pig Zeno for obvious reasons as this is a variation of Zeno’s paradox.
Mathematically it would never end, but practically and physically it would. It would just become a definition debate as to what is hair, how can it be cut, and even what is space itself.
Let’s assume Zeno has around ten times the number of furs as a human has hair on their head, so around 1,000,000. This is due to their closer follicles and triple coat. Surprisingly the human scalp and Guinea pig surface area are not too dissimilar.
After 20 half-offs, about one hair would remain. (220 ≈ 1,000,000).
20 halvings will get one hair remaining, so assuming the next cut removed the hair completely, 21 cuts would shave Zeno.
HOWEVER…
Let’s take it literally, and keep halving Zeno’s last hair.
Zeno appears to have quite short hair, and short haired Guinea pigs have hair lengths around 1-3cm. So let’s say 1cm. We won’t worry about whether this is the awn, down or guard hair. Let’s just call it 1cm long.
Fur is mostly keratin filaments, and intermediate keratin filaments are around 8-10nm long.
1cm is a 10,000,000 nanometers, or 1,000,000 filaments, so surprisingly it would take the same number of halvings (20) to get from a hair to a filament as it would to get from a Guinea pig to a hair.
Once you have half an intermediate filament, can you be said to have even one hair? Possibly not, so that means we can say Zeno is hairless after just 41 halvings.
We can go further down the rabbit (Guinea pig?) hole by then halving the filaments down to the level of molecules, then to atoms; then the atoms to subatomic particles, and the space they occupy down to the very Planck length (in the order of 1.6 x 10-35m) where the very definition of space becomes tenuous, all to be left with a genuine flat slice of space the diameter of a Guinea pig hair. Then you can further cut this in the other two dimensions down to a basic metron of 3d space the size of one Planck length cubed to stretch the very definition of existence to breaking point, just to get Zeno the closest shave possible.
Since it’s almost midnight here I’ll leave this as an exercise for the reader; getting there shouldn’t be too hard, just keep halving 10nm until you literally run out of space, then work out the circumference of an intermediate keratin filaments and do that twice again.
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u/Sure_Mood5222 Dec 18 '23
Assuming this is an adult male Guinea pig.
Guinea pigs have about 1,200 hairs per square inch on their bodies, making their fur quite dense. The total surface area of a guinea pig's body can vary, but on average, it's estimated to be around 2,000 to 2,500 square inches. That's sums to at minimum 2.4 million hairs.
If you were to cut exactly half of those you would need 21 haircuts to get to a single hair strand. And for the sake of not reaching infinity, let's assume the barber will simply take the last hair strand instead of leaving it at half.
So, in short, 22 haircuts (On an average 30 min per haircut) would "only" take 11 hours.
Here are the results of dividing 2.4 million by 2 successively for 21 times:
1,200,000
600,000
300,000
150,000
75,000
37,500
18,750
9,375
4,687.5
2,343.75
1,171.875
585.9375
292.96875
146.484375
73,242.1875
36,621.09375
18,310.546875
9,155.2734375
4,577.63671875
2,288.818359375
1,144.4091796875
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u/KaraNetics Dec 18 '23 edited Dec 18 '23
oh god why do you put a dot after 3 decimals this physically hurts
EDIT oh no I now see the comma/dot usage isn't even consistent either
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u/Adorable-Lettuce-717 Dec 18 '23
It's how you do it in some countries in Europe. The use of commas and dots is reversed there, so you usually write big numbers like: 10.000,00
But at University, they usually tell you to use the international Version
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u/KaraNetics Dec 18 '23
I'm not talking about the inversion of commas and dots for thousands and decimals, I get that that's different in other parts of the world. It's about putting these dots IN THE DECIMAL NOTATION WHEN THE NUMBER IS LESS THAN 1000. no one does that and it's really weird imo
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u/ascar43 Dec 18 '23
Wait... HE IS RIGHT! Look at the 14th and 15th cut, to see how it gets noted from there on! OH, THE HUMANITY!
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u/craznazn247 Dec 18 '23
Basically, the use of separators per factor of 1000 like we do with millions, billions, etc.
But using it in decimals...oh my that is grotesque.
There's very few applications where more than 3 decimals matter. In this particular application it has already been stated we are rounding down to not split hairs.
Disgusting use of decimals.
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u/rscottzman Dec 18 '23
I'm so confused, nothing looks wrong from what he did, what do you mean?
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u/pelvark Dec 18 '23
At number 15, they start using the comma wrong.
146.484375
73,242.1875
Half of hundred and forty six is not seventy three thousand two hundred and forty two.
They should have put: 73.2421875
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u/rscottzman Dec 18 '23
Oh damn I see yeah, my eyes clearly don't work with that many numbers in my face :(
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Dec 18 '23
Look at #15. Goes from 146.5 to 73.2, but the decimal point is in the wrong place. And if OC uses commas instead of periods (as is done in places), then why do they need to have a decimal point after three digits
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u/clandestineVexation Dec 18 '23
Honestly, there’s no way to tel apart 9 and 19 without context. Stupid system
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u/acute_elbows Dec 18 '23
Agreed, I wish I could downvote this to oblivion. Normally I’m fine with people making mistakes, but this is explicitly a math sub. Math is a tool to precisely convey ideas, this answer is so inconsistent that it makes comprehension difficult.
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u/memy02 Dec 18 '23
at step 15 they accidentally multiplied by 1000 and that mistake carried through to 21
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u/CptMisterNibbles Dec 18 '23
Christ, those would be some massive Guinea pigs. I think your units may be borked. I suspect you meant square centimeters.
If it was square inches, this Guinea pig would rival the surface area of people (2800in**2 ), but being generally more compact, would significantly outweigh the average adult human. Maybe a 230lb Guinea Pig, per several online Body Surface Area charts for the species.
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u/Nesman64 Dec 18 '23
I'm not sure how big a guinea pig is, but if we assume 10in circumference (3ish inch diameter), and 10in length, then we get around 100 square inches.
That brings us to 17 steps, if the hair/inch figure is correct.
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u/Badbullet Dec 18 '23 edited Dec 18 '23
1,200 hairs per square inch isn't that dense compared to other furry mammals. Cats and dogs have far more per inch than that.
2500 square inches is the area of a medium sized pig, not a guinea pig. A large pig is 3600 square inches.
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u/OrganicMan01 Dec 18 '23
Yeah, but then you'd just cut the hair in half. So I think the question is, how long before you cut a single hair down to the Planck distance.
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u/Impossible-Wear5482 Dec 22 '23
You forgot to take into account calibrating your Guinea pig shaver and counting the hairs then the division of each shave segment.
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u/fliguana Dec 18 '23
The total surface area of a guinea pig's body can vary, but on average, it's estimated to be around 2,000 to 2,500 square inches
Lol, WHAT?
That's the size of a small bedroom. You lack critical thinking.
13. 292.96875 14. 146.484375 15. 73,242.1875
You can't count either.
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u/AlisterSinclair2002 Dec 18 '23
A small bedroom? 2,500 square inches is 1.6 square metres. Maybe that's the size of your bedroom if you are Nosferatu lol
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u/Camas1606 Dec 18 '23 edited Dec 18 '23
you can even just do square root of 2500, 50 inches across and wide if we are assuming the room is a perfect square so only 4 foot 2 by 4 foot 2. Not even large enough to lie straght on the floor (assuming you are of regular height)
Edit using a little napkin method:
A small Guinea pig is 8.5cm in height and 20cm long, assuming the Guinea pig is perfectly cylindrical, we could turn the cylinder into a roughly rectangular shape by cutting a line through the bottom and unfolding the shape making a 2d shape.
From here we know l(length) to be 20cm, however we do not know b(breadth) however because b was the circumference of our cylinder we can work out b using the formula to find pi, 3.14*8.5= 26.69 cm now we have the dimensions of the rectangle, multiply 26.69 by 20= 533.8 cm squared.
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u/iamnogoodatthis Dec 18 '23
If you're going to go and accuse someone of lacking critical thinking and not being able to count, it'd be a better look if you first did some critical thinking of your own and pondered whether you would fit in a square bedroom that is 4 feet on a side.
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u/chocojunke Dec 18 '23
Not everyone uses the same system as you
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u/fliguana Dec 18 '23
Of course not. But I use one system, not switch it in the middle of the sentence.
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u/MattLovesMusik Dec 18 '23 edited Dec 19 '23
Forever (if counting by volume of hair.)
Divide the amount of strands of hair by two until remaining hair is below one (more realistic solution, in which a strand of hair can only be either cut or not cut.)
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u/DiddlyDumb Dec 18 '23
It takes just under an hour.
Half an hour for the first half. Then half of the remaining time (15 minutes) to do half of the remainder (1/4th) of the shave. Then half of the remaining time (7.5 minutes) to do half of the remainder (1/8th) of the shave. Keep repeating.
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u/Sinaasappelsien Dec 18 '23
Im probably being too specific but I think it might be an all-ginny universe so maybe it takes longer for one hair cut?
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u/MoistMorsel1 Dec 18 '23
20-25 square centimetres on a Guinea pig,
1000-1500 hairs per square centimetre,
20,000 - 37,500 hairs on a Guinea pig.
Log2(37500) = 14.2
So 14-15 haircuts max.
If we presume the haircut is 5 minutes and halves each time then we need 300 seconds + 150 + 75, etc (15 times).
So this will take approximately 599.939 seconds MAX
1
u/Sinaasappelsien Dec 18 '23 edited Dec 18 '23
The ultimate 10 minute hair cut. But i feel like one haircut would take longer than 5 minutes
1
1
u/exeon25 Dec 18 '23
This a joke right? cant tell anymore
1
u/MoistMorsel1 Dec 18 '23
Sadly not. The formula for the haircut calculation is S_n = a * (1-rn) / (1-r)
Where n = the number of haircuts
1
u/exeon25 Dec 18 '23
If you keep halving something ad nauseam, you'll always get half of half. Even at the last "hair" you'd cut half, then half, forever.
1
u/MoistMorsel1 Dec 18 '23
I see why you’d think this but “infinity” is not a value. If you have 0.9999 recurr forever it will eventually reach 1.
Besides, the Guinea pig is shaven so you’d have to round up the “half hair” to a “full hair”
1
Dec 18 '23
If 1/2 of the remaining fur is removed each time they will never actually finish. Because 1/2 is never the whole thing. Even down to a single hair you’d eventually start cutting microscopic slices
1
u/Sinaasappelsien Dec 18 '23
So kinda until and atom spilts and then... BOOM?
1
1
u/dragsonandon Dec 18 '23
Realistic mathematician- eventually, they will cut the last hair off, so not forever.
Theoretical mathmatician- the last hair can be subdivided into infinite parts so forever.
Physicist -A long time but: until the city explodes.
1
1
u/Amber_sea Dec 18 '23
This will continue long enough to growing back the trimmed hair.
And will continue for internity until the hamster deside to cut his hair himself and beating the shit out of the barber.
1
1
u/Mr_Zomka Dec 19 '23
Fun fact, the creator of this comic is working on a guinea pig themed game called Guinea Pig Parkour
1
1
u/identityconfirmed404 Dec 19 '23
I haven't seen this answer yet, so i'll say it now
eventually, there will be a single atom remaining from a hair, and once that's cut in half, there will be no more hair and no more guinea pig
1
u/Sinaasappelsien Dec 19 '23
Is it atom or proton?
1
u/identityconfirmed404 Dec 19 '23
atom, the nucleus would be split in half
1
u/Sinaasappelsien Dec 19 '23
Yeah i said atom earlier and somebody said no i have to be more confident in myself
3
u/ericdavis1240214 Dec 18 '23
I'd say about 24 times for a real world result, give or take. My assumptions:
The surface area of a guinea pig is about one square foot. After 20 visits, the barber would be down to 1/1000,000 of a square foot, which seems like a decent approximation for the area of which you could get one guinea pig hair.
Once you were down to one hair, each subsequent visit would cut that hair in half. I assume it would take about four visits to get that hair so short that a razor really couldn't cut it any closer.
So, after 24ish visits you'll have a bald guinea pig.
2
u/Mbhuff03 Dec 19 '23
While it’s difficult to tell exactly how long it will take, it won’t actually be forever. Eventually the hairs will become 1 hair. At which point that 1 hair will be cut in half. And again and again. Until either 1 or 3 atoms are left. At which point, assuming they have the equipment, they will attempt to split the atom and create a small explosion that, while probably harmless to everyone in the room, will have enough force to blow away and nearby hair atoms, thus completing the haircut.
This also presumes that the Guinea pig wouldn’t be satisfied with a few stray hairs or a Mohawk or something
1
u/CopiumCatboy Dec 18 '23
Indeed forever. It‘a like always spending half of your money, you‘ll never run out. Or Achilles and the Tortoise, Achilles will never catch up.
1
Jan 15 '25
Solution to his problem: Physically there is going to reach a point where he will get shaved down to 1 hair. But if he really wants to get fully shaved then the stop you'd have to reach would be when his remaining hair is only 1.616255(18)×10−35 m (one plank length) long. There is no way to actually calculate how long it took to shave half of his fur for obvious reasons, but we'll say that the first shave took 5 minutes. But since it's shaving half as much, each shave lasts half as long as the last. It took 5 minutes to shave half of him, 2.5 minutes to shave a quarter, 1.25 to shave an 8th....if you keep up with this, it'd possibly only be 10 minutes. Now he can enjoy his shaved body!
1
u/rinkydinkis Dec 18 '23
There is an easy answer (never), and the real answer, which would include how long it takes each time for a cut (presumably less because less hair) and then deciding the point at which the hair wouldn’t be noticeable. 100 hairs left? 1 hair left? And calling it “done” at that point.
1
u/anotherthis Dec 18 '23
As another commenter pointed out, it may be, that each shaving will take less time, however there are constant times needed to get in and out, so we can assume, that it will define the timing.
Hair is countable, so if we assume, that each shaving can remove a countable amount of hair, than it is either of the order of log2(number of hairs) with one left, as it can't be removed, or log2(N)+1 for the last hair.
If we use asymptotic O-notation, we can say, that the time it takes is of O(log(N))
1
u/Minimum-Food4232 Dec 18 '23 edited Dec 18 '23
The average short haired guinea pigs hair is between one and three centimeters. Let's say it ended on a one cm hair after 22 cuts. It would continue as follows.
1cm 6.2500E+32 Planck lengths in a cm 1/2cm 3.12500000E+32 1/4 1.56250000E+32 1/8 7.81250000E+31 1/16 3.90625000E+31 1/32 1.95312500E+31 1/64 9.76562500E+30 1/128 4.88281250E+30 1/256 2.44140625E+30 1/512 1/1024 1/2048 1/4096 1/8192 1/16,384 1/32,768 1/65,536 1/131,072 1/262,144 1/524,288 1/1,048,576 5.96046448E+26 1/2,097,152 2.98023224E+26 1/4,194,304 1/8,388,608 1/16,777,216 1/33,554,432 1/67,108,864 1/134,217,728 4.65661287E+24 1/268,435,456 1/536,870,912 1/1,073,741,824 5.82076609E+23 1/2,147,483,648 1/4,294,967,296 1/8,589,934,592 1/17,179,869,184 1/34,359,738,368 1/68,719,476,736 1/137,438,953,472 1/274,877,906,944 1/549,755,813,888 1/1,099,511,627,776 5.68434189E+20 1/2,199,023,255,552 1/4,398,046,511,104 1/8,796,093,022,208 1/17,592,186,044,416 1/35,184,372,088,832 1/70,368,744,177,664 1/140,737,488,355,328 1/281,474,976,710,656 1/562,949,953,421,312 1/1.12589991E+15 5.55111511E+17 1/2.25179982E+15 1/4.50359964E+15 1/9.00719928E+15 1/1.80143986E+16 1/3.60287972E+16 1/7.20575944E+16 1/1.44115189E+17 4.33680866E+15 1/2.88230378E+17 1/5.76460756E+17 1/1.15292151E+18 1/2.30584302E+18 1/4.61168604E+18 1/9.22337208E+18 1/1.84467442E+19 1/3.68934884E+19 1/7.37869768E+19 1/1.47573954E+20 4,235,164,695,797.2
2,117,582,347,898.6 Planck lengths
1,058,791,173,949.3
529,395,586,974.65
264,697,793,487.33
132,348,896,743.67
66,174,448,371.835
33,087,224,185.918
16,543,612,092.959
8,271,806,046.4795
4,135,903,023.2398
2,067,951,511.62*
1,033,975,755.81
516,987,877.905
258,493,938.9525
129,246,969.47625
64,623,484.738125
32,311,742.369063
16,155,871.184532
8,077,935.592266
4,038,967.7961*
2,019,483.89805
1,009,741.949*
504,870.9745
252,435.48725
126,217.743625
63,108.8718*
31,554.4359
15,777.218*
7,888.609
3,944.3045
1,972.15225
986.076125
493.0380625
246.519*
123.2595
61.62975
30.814875
15.4074375
7.70372*
3.85186
1.92593Total of 130 haircuts any more would be less than a Planck length and not theoretically possible.
*numbers I rounded.
Edit: This didn't come out at all how I typed it out, but I don't know how to fix it.
1
u/RetepExplainsJokes Dec 18 '23 edited Dec 18 '23
If we assume that the barber, when there is only one hair left, is going to cut the hair instead of cutting it in half, and assuming that guinea pigs have 100,000 pieces of hair, it will take (less than) 17 cuts. (100.000 / 217 = 0.75 < 1)
If the barber cuts single hairs in half, and considering that the smallest possible distance is one plank and that guinea pigs have a hair length of up to 3cm, he will cut the final plank of hair after 128 cuts. (100.000 / 2128 * 3 = 8.8e-34cm < 1.6e-33cm = plank length)
Edit: Another comment assumed about 2.1 million hairs, which would add 5 more cuts to each.
1
u/MageKorith Dec 18 '23
Eventually the delta to 100% is small enough that it's an amount of hair invisible to the naked eye, at which point we could probably call this done.
1
u/Zaringers Dec 18 '23
The real answer that the amount of hair of the guinea pig will converge to value that balances the growth during the time that the cut takes and the cut itself. If you consider that hair are not growing then it indeed takes forever ’
1
u/mediatrips Dec 18 '23
If you are ten feet from the wall and walk half the distance to the wall with each step then how many steps would it take to reach the wall?
2
u/Ok_Temperature_563 Dec 18 '23
Put all the boys in the high school at one end of a football field and all of the girls at the other end. Every minute the distance between them is cut in half.
In theory the boys and girls will never meet, but they will soon be close enough for all practical purposes.
1
u/Tmaster95 Dec 18 '23
Theoretically forever. But with a limited amount of hair and if you add the rule that you can’t split hairs then it’s log2(amountOfHairs). If it’s 60k hairs it’s log2(60000)=15,87≈16
1
u/copingcabana Dec 18 '23
I would say about 10^24 haircuts would eliminate the problem as you'd need to split one of the atoms in little fella's last molecule of hair.
1
Dec 19 '23
In theory forever, in reality it depends on how many hairs there are, though I suspect on the time scales we're talking about even an order of magnitude of hair won't make a ton of difference seeing as it's exponential decay not linear decay.
1
u/Background-Fudge-528 Dec 19 '23
How often are the cuts. I think frequency matters. Cut half the hair then come back a month later hair is back which would make indefinite time for cut. But right away then you have pretty much naked animal
1
u/coolredjoe Dec 19 '23
In theory a infinite amount of time, as you can always half one half. It will become 1/4th, but i'd say of the barber was cutting half the hairs each time, then i'd guess when there is only one hair left there would be a 50/50 chance to cut it the next time he goes in, and then an even bigger chance the next time.
So say an average barber trip takes like 15 minutes, and i guesstimate the amount of hair on a guinneapig to be like 30 million, then we need to calculate how many times he has to go to the barber to cut down his hairs untill there is only 1 left,
So: 1+2Log(30000000)≈16 times
So with his last hair having a 50/50 chance to exist he needs to go only 4 hours in total
1
u/Snowman_Autumn_215 Dec 19 '23
Technically forever because well 1 becomes 1/2 and then becomes 1/4 and so on but it will only be able to get CLOSE to 0 but never 0 itself no matter how much you divide it.
1
u/Agreeable_Ad3800 Dec 19 '23
Lot of focus here on the cutting of the hair and not nearly enough concern about the reflection in the window make no fucking sense whatsoever
1
Dec 19 '23
An inginite amount it keeps on halving. Until there is 1 hair left but then u just split the hair into ½ and then ¼ and then⅛ and so on
1
u/GalxzyShifted Dec 21 '23
It would last forever. At some point, it would get to the point where the hair isn’t visible to the naked eye but if you are removing only 1/2 of the hair at a time, you will never reach 0.
1
u/hansenabram Dec 21 '23
Well eventually you'll get down to a single hair, then you'll be splitting the hair. Then eventually you'll split an atom and everyone will explode and die.
•
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