The Birthday Paradox

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  • čas přidán 2. 06. 2024
  • How many people need to be in a room before there’s a 50% chance that two of them share the same birthday? Is it about 180, since that’s around half of 365? Is it only 100? The real answer is surprisingly much, much smaller.
    If you have just 23 people in a room, the odds of whether two get presents on the same day is a coin flip. Get 50 people together and that shared-birthday probability skyrockets to 97%. A handful more and it’s a virtual statistical certainty.
    Really? Yes, really! With the aid of tiny plastic babies and some mathematics, Kevin proves and visualizes this surprising veridical paradox.
    *** LINKS ***
    Birthday Attack Example In Hacking
    • 359 Example of a Birth...
    Birthday Attack Hash Collision
    • Birthday Attack: Hash ...
    Hashing Algorithms And Security - Computerphile
    • Hashing Algorithms and...
    Discussion On The Birthday Attack
    • Discussion on The Birt...
    The Birthday Attack
    danielmiessler.com/study/birt...
    ***********
    Vsauce2 Links
    Twitter: / vsaucetwo
    Facebook: / vsaucetwo
    Hosted, Produced, And Edited by Kevin Lieber
    Instagram: / kevlieber
    Twitter: / kevinlieber
    Website: kevinlieber.com
    Research And Writing by Matthew Tabor
    / matthewktabor
    Huge Thanks To Paula Lieber
    www.etsy.com/shop/Craftality
    Get Vsauce's favorite science and math toys delivered to your door!
    www.curiositybox.com/
    Select Music By Jake Chudnow: / jakechudnow
    MY PODCAST -- THE CREATE UNKNOWN
    / thecreateunknown

Komentáře • 34K

  • @Vsauce2
    @Vsauce2  Před 5 lety +26528

    Hey I just recently passed 4 million subscribers and just wanted to thank each and every one of you!!! Now if you'll excuse me I have a cup of babies to finish drinking.

    • @bronsonsnip0r
      @bronsonsnip0r Před 5 lety +54

      the bitdefender link is not working for me :(

    • @PunishedSenp
      @PunishedSenp Před 5 lety +51

      No problem, you deserve it

    • @ukrolelo
      @ukrolelo Před 5 lety +16

      @@bronsonsnip0r me2

    • @kumoriani
      @kumoriani Před 5 lety +59

      You're pretty much the new Vsauce anyway, might as well drop that 2 and make it official

    • @gamemak0r
      @gamemak0r Před 5 lety +56

      Hey if I'm born 1/1/1990 1AM GMT +13 and someone is born simultaneously in a different part of the world 31/12/1989 GMT -12 who is older?

  • @maverick-rs
    @maverick-rs Před 4 lety +6996

    Teacher: I have a math problem. Let's say you have 23 babies-
    Me: A problem indeed.

  • @mkaylaC1622
    @mkaylaC1622 Před 3 lety +16366

    I feel like I just learned everything and forgot everything at the same time

  • @beepduck
    @beepduck Před 7 měsíci +901

    if you are in a room with 50 people, theres a pretty low chance that one of them will share your birthday, but a very high chance that at least two of the other people will have a shared birthday

    • @rajveerkanojiya2985
      @rajveerkanojiya2985 Před 6 měsíci +33

      I understood it with the video but whoever can't they gotta look at this comment and now this reply cause
      YOU HAVING THE SAME BIRTHDAY AS THE OTHER PERSON AND BY IT I MEAN YOU HAVING SAME BIRTHDAY EXACT SAME SO THE 50% CHANCE WOULD STILL BE WHEN THERE WILL BE 182 BABIES BUT IN THIS VIDEO THEY ARE NOT TALKING ABOUT YOU SPECIFICALLY THEY ARE TALKING ABOUT ANY 2 PEOPLE OUT OF THOSE 23 I HOPE YOU UNDERSTOOD

    • @ki_yoon
      @ki_yoon Před 6 měsíci +3

      Actually, the probability in that case is about 12%

    • @zaug1561
      @zaug1561 Před 6 měsíci +7

      @@ki_yoon 365/50=7.3.....100/7.3=13.6986..... The probability is 13.6986% one of those 50 people will share your birthday.
      Edit: Disregard this, I'm an idiot.

    • @ki_yoon
      @ki_yoon Před 6 měsíci +4

      @@zaug1561 The correct method of calculation is to compute the opposite case and subtract it from 1.
      When there are 50 people, the probability that everyone's birthday is different from you is (364/365)^50 ≒ 87.18%, so the probability that there's someone who has the same birthday as you is about 12.82%

    • @zaug1561
      @zaug1561 Před 6 měsíci +4

      @@ki_yoon The chance of 1 person having the same birthday as you is 1 in 365. That seems obvious enough. So the chances of 50 people having the same birthday as you would be 50 in 365. It's that simple.
      Edit: Disregard this, I'm an idiot.

  • @Uri_Cam
    @Uri_Cam Před 9 měsíci +73

    My intrusive toughts are telling me to get 76 people that were born on diffrent days of the year and talk about this video being wrong

    • @Culvers420
      @Culvers420 Před 3 měsíci +4

      i will support your intrusive thoughts

    • @hv_2911
      @hv_2911 Před 15 dny +1

      my thoughts exactly :) but realised it would no longer be random as you "selected" people so followed a pattern

  • @aqaisback9517
    @aqaisback9517 Před 2 lety +14670

    I love when the intros are completely random due to the lack of context.
    “I have 23 BABIES.”

  • @banquo4223
    @banquo4223 Před 3 lety +43065

    To be fair, they're all babies so I assume their birthdays are fairly close together

    • @anissadunaway5415
      @anissadunaway5415 Před 3 lety +2794

      good point

    • @leenmutwakil6350
      @leenmutwakil6350 Před 3 lety +1458

      Smart 🤝

    • @ashokmandal6982
      @ashokmandal6982 Před 3 lety +737

      No, Even any adult has the same possibilities of the same birthdays as the babies , the possibility is still one of 365

    • @MarkWatney
      @MarkWatney Před 3 lety +1022

      In terms of birth year, Yes. In terms of birth date, No.

    • @Neyobe
      @Neyobe Před 3 lety +295

      Not really. A baby ranges from 0 days to 2 years old I’d say

  • @WhiskeyPapa42
    @WhiskeyPapa42 Před 11 měsíci +47

    I remember doing this as an experiment in a math class with 26 people, and we had 2 sets of duplicate birthdays.

  • @ScKTM68
    @ScKTM68 Před 9 měsíci +17

    I had this problem in a statistic exam at computer science university, and yes... they asked us also if this paradox would have been useful for softwares and security was the answer. Very interesting topic

  • @justin8287
    @justin8287 Před 2 lety +16823

    Man, imagine getting 100 people together to test this theory and then find out no one shares a birthday because you're so unlucky.

    • @fridryx8464
      @fridryx8464 Před 2 lety +863

      My whole grade when i was in school didnt share a bd the closest was like 1 day apart

    • @RunningPieBOOM
      @RunningPieBOOM Před 2 lety +459

      That's more rare so I guess its cooler

    • @cullenpike6314
      @cullenpike6314 Před 2 lety +343

      Actually that would be extremely lucky bc only like .000001% chance that happens

    • @snipergangdrob5940
      @snipergangdrob5940 Před 2 lety +174

      @@fridryx8464 My class of 25 has 8/25 kids share a birthday in the 4th grade ofc there was a pair of twins and triplets but 3 other people shared a birthday, (the triplets had a birthday on the same day as some other kid too)

    • @hajilove7337
      @hajilove7337 Před 2 lety +19

      420 likes. not liking but yeah gagaga

  • @aviksheetdasgupta1149
    @aviksheetdasgupta1149 Před 2 lety +9784

    Kevin : "I've got 23 babies"
    Me : Your wife, how is she ?

  • @JMoney47
    @JMoney47 Před 2 měsíci +42

    Who here in 2024

  • @halfcroisant
    @halfcroisant Před 6 měsíci +10

    I respect Kevin for drawing all of those lines just for 5 seconds in a video.
    Also I am born the 11th of March, pls reply. (i know I am late to the party and I know that Mark Rober is born the 11th of March as well)

  • @Grandflea02
    @Grandflea02 Před 2 lety +5388

    "I've got 23 babies"
    Gengis Khan: *That's cute.*

    • @pointzerovr8516
      @pointzerovr8516 Před 2 lety +55

      I had to look him up just to know how many kids he had

    • @StolenTorchGuy
      @StolenTorchGuy Před 2 lety +20

      @@pointzerovr8516 how many did he have ?

    • @lesymon8483
      @lesymon8483 Před 2 lety +163

      @@StolenTorchGuy _and he dissapeared, not sharing the number to anyone and leavong the question forever in the darkness..._

    • @thatguykai9140
      @thatguykai9140 Před 2 lety +32

      @@StolenTorchGuy 14

    • @speedwagon_69
      @speedwagon_69 Před 2 lety +135

      *he populated the amount he killed*

  • @griffincappin8567
    @griffincappin8567 Před 4 lety +3029

    Nobody:
    People in math problems: I have 23 babies

  • @alexissliwak9716
    @alexissliwak9716 Před rokem +14

    For anyone curious about the formula, it's a simple factorial where you remove lower numbers, keeping the higher numbers starting from 365 as you calculate the chance of NOT getting a matching date.
    For n = # of babies (23)
    And d = # of days (365)
    Chance of 2 with same date:
    = 1 - (d!/(d-n)!) / d^n
    Side note: factorial doesn't work how you would want it to when there is 1 more baby than the number of days(should multiply by 0, but the factorial of 0 equals 1)

  • @Beveyboygames
    @Beveyboygames Před 2 měsíci +7

    There is a much better way for explaining this. Pretend you are in a room of 122 people excluding you, now you have a one in three chance of sharing a birthday with another person, because there are exactly as many people as one third the amount of days in a year, which is intuitive and makes sense. Now here's the trick EVERYONE has a one in three chance of sharing a birthday with someone else in this room because of the amount of people, now 99.99997% make more sense in a room of 100 people

    • @nataliawrozek3867
      @nataliawrozek3867 Před měsícem +1

      thank you, I literally struggled with understanding before reading that

    • @Beveyboygames
      @Beveyboygames Před měsícem +2

      @@nataliawrozek3867 yeah it only feels paradoxical if you explain it really weird lol, he probably did it to keep the video going longer

  • @-r-3656
    @-r-3656 Před 3 lety +2529

    “I have 23 babies.”
    *Hold up.*

    • @itsreeya3708
      @itsreeya3708 Před 3 lety +44

      the fact that this comment has exactly 23 likes... this is what i'm gonna cry about tonight.

    • @user-ju2bk9ut8b
      @user-ju2bk9ut8b Před 3 lety +19

      It's true, i was the 23 babies

    • @SaenzGoG
      @SaenzGoG Před 3 lety +4

      223 likes, just saying, I love matches.

    • @hugolink0655
      @hugolink0655 Před 3 lety

      James Bonds constant "woman action" seems to have caught up to him

    • @emegaly1526
      @emegaly1526 Před 3 lety

      Wait a minute

  • @blackskull7x
    @blackskull7x Před 3 lety +13757

    Can't believe I'm watching this for entertainment

    • @aftabhussain4036
      @aftabhussain4036 Před 3 lety +226

      While having an exam tomorrow

    • @127ante
      @127ante Před 3 lety +41

      @@aftabhussain4036 you don’t have winter break?

    • @konosxg7178
      @konosxg7178 Před 3 lety +24

      Why not??

    • @ComradeHeydi
      @ComradeHeydi Před 3 lety +17

      @@127ante yeah? I thought every one did

    • @606movedtonewchannelsaeyou5
      @606movedtonewchannelsaeyou5 Před 3 lety +14

      @@ComradeHeydi Depends on the country, öy country doesnt have a winter break rn either. It’s ob the 22th January tho

  • @Hussary2004
    @Hussary2004 Před 5 měsíci +2

    One of the greatest videos in this great platform

  • @Tooitoi
    @Tooitoi Před 8 měsíci +6

    Me and my cousin were traveling some years ago and we found a girl who shared same birthday and name as my cousin. What is funnier it that they both lived on the same state, traveled to another country and met at the same place while celebrating their birthdays.

    • @BearPlane747
      @BearPlane747 Před 8 měsíci +2

      W profile picture.
      RIP Fly high technoblade. Techno never dies!

    • @craftworld5641
      @craftworld5641 Před 3 dny

      I guess they were old twins lost in the crowd🤣

    • @Tooitoi
      @Tooitoi Před 3 dny

      @@BearPlane747 I changed it lmao but glad someone noticed
      techno never dies!!!

    • @Tooitoi
      @Tooitoi Před 3 dny

      @@craftworld5641 yeah it was crazy!! if woulve been even better if they looked alike but the other girl was blonde with blue eyes while my cousin is a tipical latina

  • @rhinoj
    @rhinoj Před 2 lety +2477

    "If we replace our birthday babies with online passwords, . . ." ( 5:18 )
    I didn't expect to hear that sentence today

    • @B3XBP0
      @B3XBP0 Před 2 lety +30

      Or ever-

    • @kaylynnwalsh3311
      @kaylynnwalsh3311 Před 2 lety +2

      who did

    • @Penta_I
      @Penta_I Před 2 lety +8

      So did "VSauce! Kevin here. *I ' V E G O T T W E N T Y - T H R E E B A B I E S* "

    • @badkarma6392
      @badkarma6392 Před 2 lety +1

      In my basement 😏

    • @Zielllo
      @Zielllo Před 2 lety +1

      So when do you expect it

  • @chloroclymor8388
    @chloroclymor8388 Před 4 lety +4255

    He says “343” right at 3:43
    Coincidence? I THINK NOT

  • @lanewisdom6330
    @lanewisdom6330 Před 8 měsíci +6

    Damn I always watch videos like this just to get half way and realize I’ve just been daydreaming about something else the whole time, now I have to rewatch it haha

  • @chasechamberlain8721
    @chasechamberlain8721 Před 10 měsíci +3

    I would like to see 100 people come together and have a unique birthday and they are all one day away

  • @BlueJay567
    @BlueJay567 Před 3 lety +3346

    Weird that it seems everyone is getting recommended this right now

  • @joshbray5036
    @joshbray5036 Před 5 lety +2806

    Worst Villians in 2018
    =================
    2.) Thanos - Wiped out 50% of all living thing
    1.) Kevin - Erased babies

  • @LotusMouse
    @LotusMouse Před 26 dny +2

    Bro was hiding his tears when he erased the 100 baby web thingy

  • @tolik_207
    @tolik_207 Před 3 měsíci +3

    in the whole school, I knew 70 people. and 3 of them had the same birthday

  • @thejesuschrist
    @thejesuschrist Před 5 lety +52997

    You could say my birthday is a paradox.

  • @satyakamshashwat
    @satyakamshashwat Před 3 lety +2995

    Understood.. so basically, to make sure my password is secure, I should have at least 23 babies...

    • @michalsadlowski1938
      @michalsadlowski1938 Před 3 lety +10

      Simples!

    • @jasonclarkson3246
      @jasonclarkson3246 Před 3 lety +36

      Wouldn’t LESS babies be better? Because then there’s less probability of a collision occurring

    • @phjorland
      @phjorland Před 3 lety +53

      @@jasonclarkson3246 So you mean I am 100% secure because I don't have children? :D

    • @THEMATT222
      @THEMATT222 Před 3 lety +3

      @@phjorland LOL

    • @simonpichna4174
      @simonpichna4174 Před 3 lety +1

      this guy gets it

  • @b1oodzy
    @b1oodzy Před 3 měsíci +3

    For those that are interested, I ran a code 10000 times that ran the experiment with 23 babies and yes, it does come out to around 50%.
    But what I found more interesting is if we count multiple duplicates that it comes out to around 68%.

  • @JarlHolta
    @JarlHolta Před 10 měsíci +1

    The probability is arguably higher than what you solved for, if we allow cases where we do not "stop at 2", we check further if two other babies have the same birthday in that group as well, and so on.
    Now if we sum it up we end up at 20 people is on average needed to generate a 50.5% chance of shared birthdays, due to multiples groups at times.
    There are other cases as well that can further increase such a number, say 3+ share the same birthday as well.

  • @2acommunity
    @2acommunity Před 2 lety +7103

    As a teacher, I confirm this to be true. There is never a year where two students do not share the same birthday.

    • @ts214121
      @ts214121 Před 2 lety +218

      There were 9 birthday pair matches and a 3-way match in my high school class of about 100 students from over 2 decades ago. I wonder what the typical number is for a group of 100 random people.

    • @obnoxious.
      @obnoxious. Před 2 lety +49

      That would mean that there is a 100 % chance, so Vsauce's math is wrong.
      I wish I was your student, I'd have straight As .

    • @ganiz2944
      @ganiz2944 Před 2 lety +156

      I’ve never had a year where two students did share their birthdays

    • @user-ox5ir2rd6g
      @user-ox5ir2rd6g Před 2 lety +17

      @@ganiz2944 horseshit

    • @theloneliestflowerinthefie1938
      @theloneliestflowerinthefie1938 Před 2 lety +38

      In school I never shared a b. Day with anyone- mine is January 1st

  • @Alexd0t
    @Alexd0t Před 3 lety +5407

    ok so this is crazy, I asked like 9 people and turns out we all had birthdays this year, how do you even explain that?

    • @iamjohn2573
      @iamjohn2573 Před 3 lety +53

      Where did you ask tho

    • @OhQueBacan
      @OhQueBacan Před 3 lety +319

      @@iamjohn2573 lol, it went over your head

    • @nicholasvalentino3291
      @nicholasvalentino3291 Před 3 lety +171

      Dude this is a next level question

    • @youngpyro9711
      @youngpyro9711 Před 3 lety +51

      Lmao well worded 😂

    • @alexassassy5855
      @alexassassy5855 Před 3 lety +48

      @@OhQueBacan he just not misjudging people and taking for acquired the fact that people should be born within a temporal realm rather than chose their identity as a void intemporal protoss goat

  • @Disblee
    @Disblee Před 9 měsíci +3

    My aunt wanted all her kids to have the same birthday, 2 of them share a birthday, the other 2 are 2 days after the others

  • @Speckled_Jim69
    @Speckled_Jim69 Před 4 měsíci +1

    Here's one for you. When I was 16, I was dating a girl that had the same birthday as me. Same day, month and year. We were both born in the same hospital in a town that had a population of 70,000. I left that town before I went to primary school. So I never meet her until I went back to that town when I was 16.

  • @bunbunnylopunny1565
    @bunbunnylopunny1565 Před 2 lety +6010

    From a graduating class of around 23 people, the oldest and the youngest shared the same birthday just a year apart. No one else in the class did, just them. Pretty cool.

    • @emilyhellmueller
      @emilyhellmueller Před 2 lety +65

      my graduating class has the same situation, but i'm the youngest person! a lot more than 23 people but it's still pretty cool

    • @thextremekittenmdj
      @thextremekittenmdj Před 2 lety +27

      wait so how were they in the same grade?

    • @emilyhellmueller
      @emilyhellmueller Před 2 lety +41

      @madapult my birthday is august 30 and so was the other girl's. the district allowed anyone to go into that grade as long as their birthday was before september first, but ultimately it's the parent's decision. so technically, she got held back but not really

    • @MarpyPlarpy
      @MarpyPlarpy Před 2 lety +43

      @@thextremekittenmdj It is extremely common for people to start school at both the age of 4 turning 5 and 5 turning 6.

    • @InvagPrune
      @InvagPrune Před 2 lety +4

      @@emilyhellmueller same in the uk but with August 31

  • @girafpanda8886
    @girafpanda8886 Před 3 lety +1747

    “BABIES! ERASING BABIES!”
    “Alright that’s not good” lmaoo

  • @TranceSFX
    @TranceSFX Před 27 dny +1

    It helps greatly to view the day to month conversion table. I.e. day 238 of the year being in August for example.

  • @generalludwig1637
    @generalludwig1637 Před 8 měsíci +2

    interesting how this also explains how real random shuffles don't "feel" as random with both video game maps and songs....

  • @anthonythompson928
    @anthonythompson928 Před 2 lety +11779

    Wow. I did this as a fun experiment with some people in an online lobby. Turns out I had the same birthday as my twin brother

  • @ian8298
    @ian8298 Před 3 lety +4055

    _this guy:_
    *me:* winning the lotto is 50% chance because you either win or lose

    • @chrisguygamesyt9831
      @chrisguygamesyt9831 Před 3 lety +170

      Big brain move there

    • @TheAbele992
      @TheAbele992 Před 3 lety +162

      Lol I always thought as a kid that every single event had a 50% probability: either it happens or it doesn't.

    • @emraldswrd
      @emraldswrd Před 3 lety +95

      @HanHanPlayz huh, do u know what chance means lol

    • @miledacruz
      @miledacruz Před 3 lety +3

      kinda

    • @N3KLAZ
      @N3KLAZ Před 3 lety +7

      @@TheAbele992 mathematically that's actually kinda true

  • @DME3-ms4yz
    @DME3-ms4yz Před rokem +2

    Just imagine in a classroom, theres a high probability that your classmates have same birthday and I prove that

    • @minkmiau
      @minkmiau Před rokem

      Someone from my 17 people class shares my birthday

  • @rodisfishing1647
    @rodisfishing1647 Před 6 měsíci

    this is so fascinating, in 5th grade to up until now (11th) we had from 25-28 students and 2 of those share the same birthday

  • @besmart
    @besmart Před 5 lety +21344

    Kev, I have so much sympathy for you having to write on a dry erase board while left-handed. The struggle, it is real

    • @quolack6435
      @quolack6435 Před 5 lety +105

      True, true

    • @GeebleTheGarble
      @GeebleTheGarble Před 5 lety +145

      You realise its the same the other way he just set it up wrong for himself

    • @JakeLovesSteak
      @JakeLovesSteak Před 5 lety +440

      I'm lefthanded, and I'm a teacher. I teach in a classroom with a chalkboard. I've stopped writing on the board as much as possible.

    • @bardsonahill
      @bardsonahill Před 5 lety +47

      It's Okay To Be Smart what makes it harder then for right handed people?

    • @premyaragarla3600
      @premyaragarla3600 Před 5 lety +460

      Bards On A Hill We aren’t able to rest our hand on the board, at least comfortably. As you write, you start wiping everything away with you hand because you write left to right.

  • @Fayrayz
    @Fayrayz Před 3 lety +1514

    It took me WAY too long to realize that the babies were actual mini baby dolls and not popcorn. This is what happens when it’s midnight and I’m hungry.

  • @ASd-mg5gs
    @ASd-mg5gs Před 7 měsíci

    I really love michael's video, even though i don''t understand almost nothing!

  • @fruityskyline2237
    @fruityskyline2237 Před 8 měsíci +1

    At the end, I wasn't expecting you to take a candle with the number 2. That is my birthday number and the month when the video was published is also my birthday. I think maybe you could try finding some math probabilities or paradox or whatever you want for those conditions to happen ! LOL !

  • @lordjehovah3598
    @lordjehovah3598 Před 5 lety +1964

    Vsauce at the shop: Please may I have 75 fake plastic babies please
    Cashier: WTF

    • @geminin6674
      @geminin6674 Před 5 lety +10

      Were they bought from a rubber man?

    • @daemichelle
      @daemichelle Před 5 lety +16

      I thought there was 100?

    • @jadenramadhar4340
      @jadenramadhar4340 Před 5 lety

      He prob thought of that and ordered it

    • @itsbunnz5295
      @itsbunnz5295 Před 5 lety +2

      Btw I just wanna day these baby’s are from a king cake, which is a thing in the south and you find baby’s in it, it’s really weird look it up.

    • @awesomemantroll1088
      @awesomemantroll1088 Před 5 lety +18

      He's the guy we read about in math problems

  • @laloreyes7017
    @laloreyes7017 Před 4 lety +2068

    me: what’s the wifi password
    friend: it’s on the back of the router
    the back of the router: 6:17

  • @hafplace1346
    @hafplace1346 Před 10 měsíci

    thank for explaining the wtf moment i had when i first realised in my class of around 30 i share a birthday with another person, and in my year group of around 180 i share my birthday with 3 people, including the person i first mentioned in my class.

  • @lepuluke
    @lepuluke Před 8 měsíci +1

    I still can’t comprehend this. Why is it thou that we have hundreds of friends but no one shares the same birthday?

    • @MonkeShrubb
      @MonkeShrubb Před 8 měsíci

      Incredibly, unimaginably unlucky

  • @aboboborinha4811
    @aboboborinha4811 Před 2 lety +1261

    Imagine him at the store trying to buy this many babies

    • @yangsi3389
      @yangsi3389 Před 2 lety +2

      🤣😂😂😂😂

    • @cuboembaralhado8294
      @cuboembaralhado8294 Před 2 lety +18

      they sell in packs of 100, I don't know why

    • @fakefries5238
      @fakefries5238 Před 2 lety +9

      @@cuboembaralhado8294 theres some funky mexican tradition where a baby that represents baby jesus is put in a cake and whoever finds him throws the baby jesus party next year.
      I'd assume bakers would use them freqeuntly when cooking the baby jesus cakes

    • @cuboembaralhado8294
      @cuboembaralhado8294 Před 2 lety +1

      @@fakefries5238 oh, ok, that makes sense

    • @RSpracticalshooting
      @RSpracticalshooting Před 2 lety

      @@fakefries5238 we had something similar at the catholic elementary school i went to. everybody got a piece of cake and whoever got the baby won a prize.

  • @eben7248
    @eben7248 Před 4 lety +1173

    “Erasing babies...”
    *“...wait that’s not good”*

    • @Hh-dz3ee
      @Hh-dz3ee Před 4 lety +6

      I don’t wanna like cuz then it ruins the 69

    • @icantswim3123
      @icantswim3123 Před 4 lety +3

      Yes it actually is.

    • @Amdocool
      @Amdocool Před 4 lety +2

      My teacher erased my friends hand

    • @lightbombs
      @lightbombs Před 4 lety +1

      i also watched the video

    • @davisharper6704
      @davisharper6704 Před 4 lety

      Well, someone is finally against abortion.

  • @MrChriscable
    @MrChriscable Před 4 měsíci

    I used to do this at a weekly pub quiz with about 30 people and most weeks we had matching birthdays and gave them both a prize. It still surprised me every week even though I know it’s maths but it is so unintuitive

  • @rufuspipemos
    @rufuspipemos Před 6 měsíci +2

    This explains why, as a kid, I would get many baseball cards of the same player after buying just a few packs, even though there were1,400 players in the MLB.

  • @Enrique-Garcia
    @Enrique-Garcia Před 3 lety +1300

    "So, when were YOU born?"
    Oh no you don't, that's how I was hacked last time...

    • @Steve-mg8tc
      @Steve-mg8tc Před 3 lety +8

      69 likes on your comment

    • @Steve-mg8tc
      @Steve-mg8tc Před 3 lety +5

      Also I was born April 2 do you happen to be botn the same day

    • @madisonchapman108
      @madisonchapman108 Před 3 lety +2

      @@Steve-mg8tc I was born on April 3rd lmao

    • @Steve-mg8tc
      @Steve-mg8tc Před 3 lety

      @@madisonchapman108 damn

    • @hiimty4986
      @hiimty4986 Před 3 lety +4

      I’m not relevant but mine is may 17

  • @liz-ck9pz
    @liz-ck9pz Před 2 lety +515

    man's lost me when he sneaked a ! into the equation

    • @daniaalh1864
      @daniaalh1864 Před 2 lety +66

      haha the ! means ‘factorial’ - essentially the number multiplied by every number before it. for example 5! is 5x4x3x2x1

    • @Retrenorium
      @Retrenorium Před 2 lety +5

      @@daniaalh1864 isn't that the same thing but harder than to simply multiply the current number by the previous result?
      2x1=2
      3!=6 2x3=6
      4!=24 4x6=24
      5!= 120 5x24 = 120
      6! 720 120 × 6 = 600 + 120 = 720
      Etc?

    • @unlqvt
      @unlqvt Před 2 lety +14

      @@Retrenorium well yes, thats basically how calculating the factorial recursively works, meaning that you need the previous result in order to be able to calculate the next result.

    • @daniaalh1864
      @daniaalh1864 Před 2 lety +5

      @@Retrenorium if you’re in the lower numbers then sure but it’s the same thing really. when you get to large numbers like in the question, like 365!, it would be inefficient to sit there doing the work manually when you can use the ! function to get the answer immediately - for reference 10! gives you 3,628,800, so 365! would be an impossibly large number to work with. It also means you don’t have to write 365x364x363… endlessly to get to 1.

  • @brodakarat6340
    @brodakarat6340 Před 10 měsíci

    i swear every time ive come across a probability problem that has me stumped, i just negate the thing i want to find out and it becomes trivial

  • @lucasho-hz4tt
    @lucasho-hz4tt Před 10 měsíci +4

    I’m still wondering why he has 75 model babies

  • @violetforyou612
    @violetforyou612 Před 3 lety +1754

    Me Celebrating Birthday
    Random Strangers around the world:
    *Our Birthday*

  • @dominiksipos7836
    @dominiksipos7836 Před 3 lety +11050

    I'm not really sure that I understand this, but..... Merry Christmas!
    After one year... I still don't understand. Merry Christmas!

  • @the_moons_supernova
    @the_moons_supernova Před 7 měsíci

    this is on my recommended 4 years later

  • @redrob6026
    @redrob6026 Před 9 měsíci

    I once said this fact at a party, and then the first person I asked whose birthday it was had the same birthday as me. Everyone clapped as I walked away.

  • @thebookworm1613
    @thebookworm1613 Před 5 lety +903

    Breaks a marker drawing the match lines for 23 babies.
    Proceeds to use new marker to draw match lines for 100 babies.

  • @CarlaSofieFM
    @CarlaSofieFM Před 2 lety +2522

    Him: *pours tiny babies onto table* "Ive got 23 babies"
    Me: "Cool"

  • @richardfowell490
    @richardfowell490 Před 7 měsíci +1

    Think that’s the first time I’ve seen factorial (!) being used since university.
    I’m proud my education has finally come on useful😂

  • @pirimi
    @pirimi Před 4 měsíci +1

    I love probabilities and math like that, but when it comes to school math it's like we're arch nemeses

  • @corbanspittka4436
    @corbanspittka4436 Před 3 lety +651

    Imagine walking into a room with a single light and a man with a table with like a 100 tiny babies in a circle drawing lines....merry Christmas everybody

  • @dylanwoodside3102
    @dylanwoodside3102 Před 4 lety +2726

    Imagine Kevin going to the store and just buying like 100 tiny babies

  • @MonkeShrubb
    @MonkeShrubb Před 8 měsíci +1

    Bro was drinking babies, it will be interesting to see how he will explain this to the police later

  • @CarrotStopper_382
    @CarrotStopper_382 Před 8 měsíci +1

    Omg the one time that factorials are ever used

  • @Milestone783
    @Milestone783 Před 2 lety +790

    teachers be like: “you didn’t show your work”

    • @venum9663
      @venum9663 Před 2 lety +58

      “That’s not the correct way of solving the question even though you got the right answer”

    • @emsiyes
      @emsiyes Před 2 lety +22

      "And because of that, I'm giving you an F"

    • @speaar
      @speaar Před 2 lety +14

      “And that’s why you lost your job”

    • @Kenobisan02
      @Kenobisan02 Před 2 lety +13

      "The streets are calling my name"

    • @raymiller5895
      @raymiller5895 Před 2 lety +10

      @@venum9663 I only had one teacher that didn’t do that, she said, “I’ve never seen anyone do it that way before, you got the correct answer. Now let me tell you why that won’t always work. Oh, I’m not marking this as wrong

  • @greta8555
    @greta8555 Před 2 lety +1932

    can’t believe I clicked on this video thinking it was called the britney paradox

    • @antoniovergotti1895
      @antoniovergotti1895 Před 2 lety +9

      Same_

    • @javieraossandon2713
      @javieraossandon2713 Před 2 lety +43

      LMFAOOO I can imagine you being like "why the hell is he putting babies in the table"

    • @rbyln3112
      @rbyln3112 Před 2 lety +10

      I thought it said “happy birthday paradox” ;-;

    • @Helianthus_
      @Helianthus_ Před 2 lety +16

      Oh baby baby, how was he supposed to know that something wasn't right here?

    • @dr.downvote
      @dr.downvote Před 2 lety

      Can't blame after seeing the name Greta! Jk, no offense to you, all goes to Greta thunberg lol

  • @NxnjaSenpai
    @NxnjaSenpai Před 8 měsíci

    Speaking from personal experience. I went to a small high school where each elective class was made up from the same pool of about 50 kids all born within a 6 year range. Not only did the yearbook show that two of my friends shared the same birth day but they both shared the same birth date. They were not related.

  • @jetplanewastaken
    @jetplanewastaken Před 7 měsíci

    0:06 i love the way he just says that nonchalantly

  • @wateenabutaha4871
    @wateenabutaha4871 Před 2 lety +1234

    I did not understand a word besides babies and birthday 👍🏻

    • @evangelinegamali3374
      @evangelinegamali3374 Před 2 lety +7

      Seseme seed

    • @husseinazher
      @husseinazher Před 2 lety +1

      Me2

    • @applepie1272
      @applepie1272 Před 2 lety +2

      oh Babies and Birthday's are TIGHT

    • @lucytenden7975
      @lucytenden7975 Před 2 lety

      that’s bc he was trying to make it sound cool and confusing by calling them babies when he rlly means any human not just babies. But if u think about it, obviously there’s a big chance 2 out of 100 people would have the same birthday out of 365 days just not born on the same year.

    • @hicrhodushicsalta4382
      @hicrhodushicsalta4382 Před 2 lety

      @@lucytenden7975 that's cause it's simple probability (n/k) everyone does this in 9th Grade or so...

  • @nicholaswensink2314
    @nicholaswensink2314 Před 5 lety +574

    A lot of people are misunderstanding this, saying something along the line of “but there are 100 people in my ______ and I share a birthday with none of them”. The probability here is saying there’s a 99.7% chance that at least two in the sample will share a birthday not that you specifically will.

    • @mulymule12
      @mulymule12 Před 5 lety +42

      Yeh, make's perfect sense with an ounce of thought. 99.7% chance that 2 will share a birthday in a sample of 100, but that still leaves a 1/50 chance that will be you. Or 2%

    • @azlan194
      @azlan194 Před 5 lety +54

      Yeah, a lot of people are confused about it. Another way to put it is like, the probability of SOMEONE winning a lottery this month is very high (almost every month there's someone winning lottery) but the chance of you winning it is almost 0%!

    • @MrHasas963
      @MrHasas963 Před 5 lety +2

      The first comment i get. But why did two ppl just confirm what does not need confirming? You you think the guys is right, theres the like button.

    • @MrHasas963
      @MrHasas963 Před 5 lety +1

      @@mulymule12 the way i think you should look at it tho is that there is a 50 %chance from your perspective. You will either find one or not. I wouldnt bother because i dont rly want to meet a 100 babies

    • @atriyakoller136
      @atriyakoller136 Před 5 lety

      I am a teacher who teaches small groups of students. I have a birthday on December 31st. And in October I had two groups where I had a student with a birthday on the same day. It was cool.

  • @zoe127
    @zoe127 Před 9 měsíci

    CZcams really showed me this on my recommendations on my birthday

  • @cay2008
    @cay2008 Před 7 dny

    Imagine him going to the store buying 75 babies. Imagine some of the employees at the store

  • @BAC0NWOW
    @BAC0NWOW Před 2 lety +889

    stares into camera... "ive got 23 babies"
    this is why I love vsauce

  • @tigerwoods4034
    @tigerwoods4034 Před 2 lety +1869

    I went to high school with about 800 guys and everyday during announcements they would shout of the birthdays. It was not uncommon that nobody had a birthday that day. I didn’t know how statistically crazy this was.

    • @nathanbensoni469
      @nathanbensoni469 Před 2 lety +2

      Hmmmm

    • @stijnkemper7103
      @stijnkemper7103 Před 2 lety +159

      I rlly need to think to understand this sentence, u could'va said: It was common that nobody had a birthday tbat day😂😂😂

    • @PurpleMoon799
      @PurpleMoon799 Před 2 lety +19

      probably in august 😉

    • @MaryJane-tp3qd
      @MaryJane-tp3qd Před 2 lety +13

      My freshman year had 1,800 kids and now I wish they told us people birthdays :(

    • @HannaSis
      @HannaSis Před 2 lety +27

      My school does the same thing and I don’t think that anyone shares the same birthday except for these 3 girls in my class who were all born on the same day, during the same hour 😂

  • @TFB-GD.
    @TFB-GD. Před 11 měsíci +1

    Watching this on my birthday :)

  • @DBZVelena
    @DBZVelena Před 6 měsíci +1

    so this is why you should use numbers, letters, capitalization and symbols in your passwords.

  • @unboiledegg5765
    @unboiledegg5765 Před 5 lety +2013

    2:50 “Babies.......... erasing babies.......
    Ok that’s not good”
    -Kevin 2018

    • @MaxTheCat-eh5ts
      @MaxTheCat-eh5ts Před 5 lety +2

      Unboiled Egg oof

    • @mechacode8527
      @mechacode8527 Před 5 lety +14

      Wow... I have read comments that claim to see a comment quoting the guy in the video in the exact time the guy in the video says it... I thought it was very hard for that to happen, but that has just happened to me with your comment.

    • @KitsuneCentral
      @KitsuneCentral Před 5 lety +14

      Mr. VSauce, I don't feel so good.

    • @gqh007
      @gqh007 Před 5 lety +28

      Fetus deletus

    • @GarfieldPhone
      @GarfieldPhone Před 5 lety +9

      Abortion

  • @BrooklynBwoii
    @BrooklynBwoii Před 3 lety +1429

    As long as 70 people are watching this video at the same time, there is a 99.9% chance that they will have the same death day but in different years.

  • @Wisty_Editz
    @Wisty_Editz Před 7 měsíci +1

    That’s why every year in my class, there’s at least 2 people with the same birthday😂

  • @rises..the_moon
    @rises..the_moon Před rokem +1

    I don't know why i watch this
    I randomly clicked it even though i don't understand the whole video i still watch it till the end 💀

  • @serenecatweather5694
    @serenecatweather5694 Před 2 lety +4666

    I can confirm this theory. In my class of 10 people, 1 dude has the EXACT same birthday as I. In another class of mine, of 22 people, someone else shares the same birthday as me too. It’s a miracle !

    • @ssvn7vii
      @ssvn7vii Před 2 lety +55

      Well my birthday is New Year’s Eve, so can’t relate.

    • @mattthedestroyer2804
      @mattthedestroyer2804 Před 2 lety +140

      That's not a scientific confirmation

    • @natetollett5515
      @natetollett5515 Před 2 lety +61

      Well that actually isn’t backing this. The chances of you sharing your birthday with someone in your class if 10 is still 10/365

    • @Monmon-ve9qp
      @Monmon-ve9qp Před 2 lety +18

      that's cool! Our class has 50 students and none of them had the same birthday as me😭😭

    • @leafsculpture
      @leafsculpture Před 2 lety

      I met someone from my own school who had the same birthday

  • @kaiserxyozni4786
    @kaiserxyozni4786 Před 5 lety +905

    Can we just admire that Kevin literarily purchased 100 baby dolls

    • @dimi7621
      @dimi7621 Před 4 lety +18

      And also that he gave the effort to put them all one-by-one in place

    • @jadesketch1726
      @jadesketch1726 Před 4 lety +4

      Do you know where he bought those ?(i want little baby dolls)

    • @nattidahelsinghof2306
      @nattidahelsinghof2306 Před 4 lety +1

      Jadesketch no but i wan one

    • @payton4786
      @payton4786 Před 4 lety +7

      you can get them off amazon, all the juniors at my school has littered the school with them

    • @purgatorian1616
      @purgatorian1616 Před 4 lety +3

      @@payton4786 must've been inspired by Jordan Cunninghams hiding mini babies video

  • @maybemintmochi_
    @maybemintmochi_ Před 8 měsíci +1

    I was so invested in this as a leap year baby T-T

  • @patrickbrowdy5173
    @patrickbrowdy5173 Před 8 měsíci +1

    I'm not sharing my birthday and location on a public forum, Kevin.

  • @stone1290
    @stone1290 Před 5 lety +917

    Kevin: "VSauce, Kevin here!"
    Kevin: *_"I've got 23 babies!"_*
    *Jesus Kevin what happens after the show?...*

  • @hannahturner6629
    @hannahturner6629 Před 3 lety +1438

    it took me so long to realize the “babies” weren’t popcorn

  • @clayrester9342
    @clayrester9342 Před 7 měsíci

    this makes sense now that i think back to when i was in school... there were always overlapping birthdays.....

  • @everettmc4795
    @everettmc4795 Před 5 měsíci

    I'm watching this on my birthday, so I just think that that's pretty cool

  • @kuttispielt7801
    @kuttispielt7801 Před 5 lety +1245

    So how many babies do you want?
    Vsauce: yes

    • @sebastianstan9655
      @sebastianstan9655 Před 4 lety +12

      Chinese/Indians : *YES YES YES*

    • @robertpietraru1939
      @robertpietraru1939 Před 4 lety

      @@sebastianstan9655 xD

    • @pianoguy9300
      @pianoguy9300 Před 4 lety

      So... vsauce is sexchatting?
      Vsauce: *Yes*

    • @Mr_Bones-yf1sw
      @Mr_Bones-yf1sw Před 4 lety

      New drinking game idea! Every time he says either birthday or baby in this video take a sip!(If you end up in the hospital say it was the guy above or below me)

    • @tigershark8867
      @tigershark8867 Před 4 lety

      @@sebastianstan9655 The Chinese have a two-child policy tho...
      They want the extra babies for lunch then?

  • @mattson4552
    @mattson4552 Před 5 lety +741

    kevin- "I've got 23 babies"
    *FBI OPEN UP*

  • @user-qz3oi9qc2j
    @user-qz3oi9qc2j Před 4 měsíci

    This was once explained in a statistics class. One student just couldn't believe it so the lecturer asked everyone to share their birthday in turns. I think we had gone through only 10 students when it turned out two persons had birthday ON THAT EXACT DAY. This was a literal "and then everyone clapped" moment as, well, everyone did.