Can you solve the dark coin riddle? - Lisa Winer

Practice more problem-solving at brilliant.org/TedEd/
Solution to the bonus riddle mentioned at the end: brilliant.org/tededcoinflip
You heard the travelers’ tales, you followed the maps, and now, you’ve finally located the dungeon containing a stash of ancient coins. The good news: the wizard who owns the castle has generously agreed to let you have the coins. The bad news: he’s not quite as generous about letting you leave the dungeon ... unless you solve his puzzle. Can you solve it and get out alive? Lisa Winer shows how.
Lesson by Lisa Winer, animation by Artrake Studio.
Thank you so much to our patrons for supporting us on Patreon! Without you this video would not be possible! سلطان الخليفي, Marylise CHAUFFETON, Marvin Vizuett, Jayant Sahewal, Joshua Plant, Quinn Shen, Caleb ross, Elizabeth Cruz, Elnathan Joshua Bangayan, Gaurav Rana, Mullaiarasu Sundaramurthy, Jose Henrique Leopoldo e Silva, Dan Paterniti, Jose Schroeder, Jerome Froelich, Tyler Yoshizumi, Martin Stephen, Faiza Imtiaz, Khalifa Alhulail, Tejas Dc, Govind Shukla, Benjamin & Shannon Pinder, Srikote Naewchampa, Ex Foedus, Sage Curie, Exal Enrique Cisneros Tuch, Ana Maria, Vignan Velivela, Ibel Wong, Ahmad Hyari, A Hundred Years, eden sher, Travis Wehrman, Minh Tran, Louisa Lee, Kiara Taylor, and Hoang Viet.

[@TEDEd]

If you want to practice more problem-solving for free, head to brilliant.org/TedEd/. If you want to signup for a "premium" account, hurry! The first 833 of you to visit that link will receive 20% off the annual premium subscription. Thanks to Brilliant.org for supporting this video!

[@cobalt6653]

TED-Ed n

[@friedwater6519]

but why 833

[@notosis6482]

TED-Ed I

[@aryavmenon7591]

TED-Ed is the answer 6 for the bonus riddle ???

[@raniabashar7955]

i have a riddle for you😐you you you u u u

[@chrisj403]

If my nose came out of my forehead I wouldn't be so generous either.

[@simplename9928]

Garlic Prince lmao

[@RenegadeShepTheSpacer]

Shalom.

[@lucasmellor7070]

Hahaha

[@davidchivu7373]

Yes

[@potatobeans9893]

I just noticed that 😂😂😂

[@theob3515]

When the torches went out, there shouldn’t have been a problem. His eyes and teeth glow in the dark

[@cyclops6506]

Actually, yeah

[@326inminecraft]

Theodore Budgen so is his eye

[@monticha3274]

Theodore Budgen lol

[@aregulargamer4144]

What is he a garden dragon from how to train you dragon books

[@tracydu8052]

Maybe you have GREEN eyes. So you should just ask the Willard to leave do you won’t be tossed in the volcano

[@robyyc4960]

Riddle: "There is a surprisingly easy solution." Me: OH I KNOW! (Pulls out quantum physics manual) Me: Now, let's see here...

[@tomcarr7732]

i'm sure you will get it now lol

[@Kirtan007]

Well if the velocity of the coins is zero then the position of the coins is not defined.(assuming that you don't affect the coins while observing)

[@NuggetOG]

i will use quantem magnetism to make the heavier side go down, leaving all coins to be in the same side, and then count the amount of coins andthen split it equally

[@prerakgames4668]

Nothing has anything with quantum physics

[@jeremythomas4744]

Actually if you toss the coin the gold side should fall on the bottom, as gold is denser than silver. Do that with every coin a few times just to be sure then split them in any pattern, then you get 0 silver sides up on both sides

[@dudeitsmilena]

this is the only riddle i have ever actually solved from ted ed. i just want to mark this moment with a comment. amen.

[@ShreshthaGusain]

May your soul feel relieved

[@thespeedyyoshi]

Wooooo

[@anngeorge3732]

I congratulate you

[@Depresssedbitch]

Hey me too! Amen

[@ireneboyle4261]

Congrats!

[@rohanjeetdas5707]

"You just realised there's a surprisingly easy solution." No I didn't.

[@zkhdillard]

Rohanjeet Das that just made me feel dumber 😔

[@canadaisntreal4817]

ikr

[@yukimori_shirei]

Ye true

[@kyambaddemoses8884]

hahahah

[@sinoroman]

>you counted that there are 20 silver coins HOW?? but, don't remember the top parts??

[@meatman6908]

step 1: confirm you have green eyes step 2: ask the wizard to leave

[@chrisoez]

System 32 Not Found nice

[@ibperson7765]

Jeboy Ajax 32 likes u guys r freakin me out

[@user-ws9ko1pu1y]

iDonTgeTiT

[@kamrynhall2550]

yarrow it’s another riddle about people with green eyes trapped on an island

[@narwalmations]

yarrow r/woooosh

[@keheck]

The real riddle is: How did I remember seeing 20 silver-up coins, when clearly I was occupied with other studd?

[@Ponera-Sama]

And some of the silver facing coins were underneath other coins

[@RafaelMunizYT]

this man's eyes are like a fourth of his total height, they gotta be good

[@reprochr2804]

studd=stuff

[@drewhuang5517]

Me: ok so I'm gonna count out 20 coins and flip em' over Me: drops the coins Eccentric wizard: so you have chosen...death

[@cjfdnqkn4374]

Me: I had a good life...

[@risingraisings7012]

I'm starting to think I'll never pause one of these

[@mountain_pro]

rising raisings your profile pic is trigring my OCD

[@mango6418]

Also looked like hair

[@chandlerbing3723]

I use the dark theme.😂

[@tantiwahopak101]

@@chandlerbing3723 same mate. 😁

[@KGNYC112]

dat potatoe And I tried turning your potatoe into chips.

[@sushiroll7013]

1:40 Look at that smile.... It will haunt my nightmares forever.

[@bobjoe1832]

I think it’s kinda derpy lol

[@majesticduck1534]

"He's not as generous about leaving the dungeon" (Locks the already locked door with chains.) Me: what are you doing?

[@petercarney5928]

For the final riddle, you have to have an odd # of gold coins to be able to flip them to all gold. Including the #'s 1 and 3. If any of the 3 coin piles start with an odd # of silver coins, it wont be possible. This includes starting with 3 coins facing silver up and 1 coin facing silver up. This means that 4 out of the 8 3-coin piles are able to be turned to all gold solutions

[@pradithhindupur6295]

Thank you for telling the answer

[@richardl6751]

Also, only six of the seven combinations are shown. The right column contains two duplicates and the two combinations are missing, gss and sgg.

[@imAnonymous_19]

​@@richardl6751gss is shown as ssg and sgg is shown as ggs to denote the fact that the pairs are the same point in the riddle because of parity symmetry, for anyone who is flipping and jumping between the 8 combinations shown there. Thus confusion is avoided.

[@Aunini]

Essentially, since silver coins can only be removed in pairs (flipping one of each becomes...one of each), there needs to be an even amount of silver coins showing.

[@Buzzgrim]

"He's not gonna let you leave the dungeon. Because he wants to do a puzzle with you.." .....Of course he does.

[@TheKYLEdavid]

When you have infinite power and time, you get bored.

[@oldcowbb]

i want to play a game

[@GTron13]

**tries to like a million times but KZbin won't let him :(**

[@bitter-unicorn]

"THIS REMINDS ME OF A PUZZLE" "...But can I just leave?" "NO IT'S PUZZLE TIME PEASANT"

[@ryantan3841]

lol i have the same name as you

[@dumptruck3591]

What I learned from watching ted ed riddles: I'd have to be a genius mathematician to easily solve everything unrealistic

[@audreydeatherage2131]

most of them yes. this one tho is more about understanding a simple concept. all the math was only them proving that concept, the math isnt needed to solve the puzzle

[@liviorocco7817]

Solved this, never had been any good in maths. I just questioned why the rules were formulated that way

[@chattyclan9320]

true

[@m3mori]

@@liviorocco7817 yeah there’s explicit emphasis on the fact that you can flip coins, once you figure that out you’ve got more than half of the answer

[@readoesstuff8171]

3:08 He shouldn’t be interested in gold He should be interested in magic tricks

[@Rainy_R]

*yes*

[@pahoellyyy]

"You just realized there's a surprisingly easy solution" Of course!! Keep watching the video

[@anuragshukla1891]

hahaha.....good one

[@joeypencil5368]

In any Ted-Ed riddle, there is always at least 2 guaranteed treasures: how to solve the riddle, and comments like these HAHAHAHAHA!!!

[@shadowshot347]

Haha good one

[@poisonedmaple6874]

iTs ACTuaLLy sUpRIsINgLY sIMpLE

[@wingeddance]

Plot Twist: it wasnt made out of real gold or silver and the true treasure was knowledge

[@robsonneves6189]

Sara Zeru Does not make sense because the wizard did not share any knowledge with the explorer, the explorer just knew the solution to the riddle.

[@enodragon9635]

The real treasure was the friends we made along the way

[@jedidiahslaboda5620]

No, it was the Stygian coins.

[@pedrogomes5796]

The real treasure is the knowledge that wizards are douchebags.

[@rawnuhld]

headass

[@hvonwolfenstein2638]

This riddle is much more impressive (fun to show people) if you do it with a deck of cards.

[@BrettAbaurrea]

Oooh how do you do that?

[@mintmayden]

The number of face up coins or cards is arbitrary

[@janjeikobu5163]

So you do it with 21 cards? Instead of 20? Right? Right? RIGHT?

[@lizard_ow7145]

@@janjeikobu5163 no, so u basically take any number of cards, and flip any number of them over, then you blindfold yourself or something and take the exact number of the the cards you flipped over from your pile. (it could even be all of them)

[@justjuniorjaw]

It happens that I watched Michael's video before this so, here's how it is done with a deck of cards : kzbin.info/www/bejne/l6KunKqKgLyKi7M

[@thevioletspiral]

TED-Ed should get an award for their loyalty to brilliant

[@ariamae2034]

Man, imagine if this person hadn’t had the magic ability to see and count exactly 20 coins being silver side up initially

[@erickpoorbaugh6728]

Technically, it doesn't say you only have one chance. You could flip one coin into a new pile, then flip a second coin into the new pile, etc., and when the number of coins in the new pile is the same as the original number of silver-side-up coins, you'll win.

[@supercanadian0640]

Another riddle I can't solve :D

[@aaltynkaldybay48]

The Ace Of Spades Hucknall the same time and money to you are looking at the moment and I have to travel around the world of work

[@hannapy303]

You are not alone.

[@Gilgameshh]

this one was one of few riddles i got everything correct in. It was a dead giveaway when he said there was a surprisingly easy method of getting it right.

[@alxxanderr]

Same 😂😂😂

[@bearheart2009]

Just bite the coin. If the gold side is real it will be softer than the silver side and make a dent =D

[@ZHBG-ll7fy]

Did this expeditioner seriously not have a flashlight on them wtf

[@TheKYLEdavid]

Maybe he landed on it when he fell in that hole, breaking it.

[@ZartaxtheWise]

Wizards do magic?

[@yiggyna1938]

ZHBG 9224 Its a hypothetical!

[@tripledddsanimsandstuff9887]

Why no bag either

[@Muheeb_4]

I don't know why this made me laugh so much

[@owenharris9690]

For the bonus riddle: If I am not incorrect, any pile with two silver coins can become all gold. If the two are adjacent you simply flip them and leave the initially gold coin alone. If they are on opposite sides of a gold coin then you flip each of them over once, the gold coin is then flipped twice since flipping coins on either side flips the middle coin and this remains gold, this leaves you with three gold coins.

[@MasterTrickShot]

Bro watching these riddles high is such a mind blown moment

[@himanshu6188]

Finally a riddle video after a long time! Make more of these please :-)

[@bonbonsquad7465]

himanshu sarin I agree I miss these riddles

[@tristinmccleaf3968]

Me too, once I saw this I got excited. I’ve literally watched all of them and I have just been waiting for them to post riddles

[@bonbonsquad7465]

Tristin McCleaf me too

[@pedrogomes5796]

Actually, because pure gold used in old coins is soft, you can bite both sides of a coin and the one with a dent is the gold side, so there IS a way to determine which side is facing up. According to the riddle, that's cheating, but if you're stuck in an underground dungeon in total darkness cheating is the best option 😁.

[@lancerlord9939]

pedro gomes Or, since gold is denser, you can lay the coins on their sides, and the silver side will be on top

[@pedrogomes5796]

Puzzles should prize the most creative answer instead of the "right" one.

[@PXDessert]

Gold is "soft". But you can just bite into it. It's called soft because It's not as dense as other metals.

[@kevinlam1956]

James K. No the material of your teeth has a higher hardness scale than gold, which means if you bite it the gold will give

[@yourmom-hm1hn]

But would you REALLY want to bite a bunch of coins?

[@jasonzhou8274]

Why don't you just bring one or more of the following: 1: Flashlight 2: Matchbox 3: Cellphone 4: Literally anything that can create light Edit: Wow, I make a list of things people should have while exploring and it gets more then 150 likes. Not that I'm complaining.

[@theamazingcatwizard3654]

Audrey: The Girl in the Corner those don’t count, it’s cartoon logic.

[@xenophanesbringsthepain1229]

@@theamazingcatwizard3654 you're a wizard kitty -Dogalf

[@autumnveir1168]

5. The wands at the truel

[@Inkyminkyzizwoz]

*more than

[@yuchunxu8417]

6. the literally GLOWING eyes and teeth

[@xck]

The real question is: Why are your maps crumbling?

[@shinyagumon7015]

They are very old maps

[@psalmdealer]

0:35 the wizard is giving you the finger

[@ZBreezee-nb2rl]

Did that warlock just flip the bird at me?!

[@staceykhoo5971]

sharp eyes m8

[@chitimmins2168]

0:36

[@johnapril1861]

This made me lol

[@lucky9293]

HEY! DON’T FLIP ME THE BIRD!

[@parkchanyeol1544]

Although I didn't understand anything, I'll still pretend I got smarter just by watching this

[@boop6171]

Park Chanyeol Same lmao

[@supremelordender5705]

ikr

[@buddiebudd547]

😂😂😂😂

[@Gingergent07]

Truth hahaha

[@isasitems552]

Park Chanyeol lol same

[@ThechiefCE117]

There is a way I have found out, but a little more difficult. Stand the coins up on its side. Since gold is more dense than silver, it’s side is more massive, assuming that the silver and gold go right down the middle of the coins in equal volumes. That means when you put the coin up on its side, it will always land gold side down and silver side up.

[@abhie8898]

The thing is its not the material gold its the color gold and the same for silver

[@eduardoxenofonte4004]

@@abhie8898 nah they'd probably use the material instead of paint based on how old they seem to be

[@sidg3003]

It said in the rules that you cannot put the coins on their sides

[@savanareherman654]

“You realize there is a simple solution” Yea, relight the torches with the embers in then

[@theoverseer393]

I just though "ill try spinning, thats a good trick!" i mean, gold is denser, right?

[@joeyg2488]

That’s not how that works

[@SonicLoverDS]

Even if that worked reliably, you now have no idea whether that coin was silver or gold to begin with, and with hundreds of coins in the pile it's not plausible to spin every single one of them.

[@Amnesia1998]

@@SonicLoverDS Why not? It's not like you have anything better to be doing.

[@CavCave]

I thought they were just painted silver, not actually made of silver

[@alanjones8573]

I don’t think so?

[@alexchen2519]

This is the first puzzle I could do in the entire series. I tend to overthink problems, so when he said there is a surprising solution it was actually a huge help.

[@some_random_human_being1891]

TED-ED: pause the video to figure it out yourself Me: NOPE!! no way am i figuring this out

[@user-sn8sj6dg6j]

same :)

[@RobjectionableContent]

For the bonus riddle, I figure that if there's an even number of silver-side-up coins in the arrangement, then it is possible to make them all gold-side-up, whereas if there's an odd number then it's not possible. This is because each flip you make always affects exactly two coins, and adding 2 to or subtracting 2 from an odd number will always leave you with another odd number but 0 (the number of silver-side-ups you want) is an even number.

[@t_kon]

That's correct, but a better reasoning is as follows Assume the number of face up silver coins to be x At any operation, you're either 1. Adding 2 to the number of face up silver coins (flip 2 golds) 2. Subtracting 2 to the number of face up silver coind (flip 2 silvers) 3. No change (flip 1 silver 1 gold) Thus you'll always change the number of face up silver by 2, and no matter move you do, you can't change odd into even just by adding even numbers, so that proves it's impossible if the number of face up silver is not odd. Then you'll only need to prove it's possible for all odd configuration.

[@someone.-gi7zr]

​@@t_konso the answer to the puzzle is 3?

[@WiWillemijn]

Just use your phone light

[@completevoidinpfp7129]

He has no phone

[@Anonymous-hv2zc]

Well, it looked like he was in a forest and last time I checked there is no signal nor internet in the forest.

[@ItzRoger]

The year is 1985

[@theluckygamer10]

Wimsem - Tekenen & Knutselen no phone ignaramus

[@clementejoseph3854]

Ciel Moro you don't need a signal to use your phone light lol

[@HORRIOR1]

I misunderstood the given riddle and thought both piles had to have same amount of coins :/ Still that is a very clever solution.

[@courtney-ray]

HORRIOR I thought the same thing

[@zanonymousruiz9697]

This solution is so elegant and obvious in hindsight- Colour me impressed!

[@Edivelsandoval7994]

0:35 when wizard does middle finger

[@Wall_nut77]

Have you heard of the pointing finger?

[@TheWorldsLargestOven]

Bro doesn't know what an index finger is 💀

[@arcticwind1368]

plot twist : the silver coins at the beginning weren't 20.They were 21

[@kaliyanelson6106]

That... O.o Uh... That's an odd number... *THE GAME IS RIGGED!*

[@KineticManiac]

@@kaliyanelson6106 Not really, since you can flip any coin you want, you can still win. You can start with 21 silver side up coins and have 0 or 100 silver side up coins in each pile. Doing this in the dark is an issue though.

[@nero9506]

@@KineticManiac Yeah, as long as you are able to count them beforehand though, otherwise it would be useless

[@Victoria3WorldConquerer]

@@nero9506 No you could just take one random coin and flip it over then do the same thing over and over until the door opens

[@nicholaspratt8473]

@@Victoria3WorldConquerer yeah this is one of the riddles that are someone open-solved with a loose end-point

[@firstnamelastname8684]

heres a tough riddle How many shrimps do you have to eat, before you make your skin turn pink? ok ill stop

[@cheerfulgoat]

How about this riddle: Hit or miss? I guess they never miss, but I'm not sure.

[@zytlib6758]

cheerfulgoat come on

[@axelpetersson5787]

First Name Last Name idk, wouldnt wanna try. If i eat too much i’ll get sick (Cus shrimps are pretty rich)

[@cheerfulgoat]

I have another riddle. Can I be Tracer? They're already Tracer though...

[@KGNYC112]

Audrey ARNOLD Shrimp is my weakness 👀 👅💦 🍤

[@Munchkin.Of.Pern09]

Me looking at the bonus question: “If the number of gold coins facing up at the start is one or three, then it can be made all gold.”

[@Mananpicar]

Answer for last riddle: The ones with 1 or 3 gold coins, since you always move 2 coins. An even number + another even number, will always be an even number, therefore, you can never make 3 gold coins, no matter what you do, you can only get 0 or 2.

[@rahborchoudhury3277]

Last riddle is easy. Step 1 first try to make all 3 silver

[@TheHealthyCow]

What about the giant hole he fell through and just using that as light lol

[@wrylysmiley]

Yeah i thought that as well, a much slower alternative to the video's solution.

[@wrylysmiley]

We can hardly ask questions, can we?

[@golatificon]

There is no light at night :p

[@theflyingtofu-4487]

TheHealthyCow OMG YOU WATCH THIS TOO? #NOTICEMESENPAI!

[@Minty_Mentos_]

golatificon wait until day

[@mariasennani4089]

0:18 Good news: Yeees! Another riddle! Bad news: I can’t solve it

[@shawnfunny2540]

There is a surprisingly easy solution: Cut all the coins in half

[@cjfdnqkn4374]

lol ur a genius

[@kaboomwinn4026]

Or biting the coin and if what ever the the top or bottom coin Is soft then it Is gold if it hard the it silver. This way I can I can divide equally with silver side up and gold side down.

[@Andrux0821]

Gold and silver have a distinctive sound. You can use the ping test to decide which one is silver and which one is gold. Silver will usually sound like a C and gold will usually sound like an A. This is usually the case no matter the size of the coin, unless the actual silver/gold content is super low. Even then, a 35% war nickel has a distinctive sound over a copper-nickel nickel.

[@finchfamily7268]

Non-perfect pitch people tho

[@Andrux0821]

@@finchfamily7268 perfect pitch does help, but you don’t need it. You can do it just fine using relative pitch if you have a sample sound and you compare it to the one in question.

[@kumarshumar]

I'll just lay down on my bed, and not solve anything. But watch the full video, and feel a sense of accomplishment.

[@AAG414]

"You just realized there's a surprisingly easy solution" next time, bring tnt to blow the walls up

[@yellowlama2732]

No a Hydrogen bomb is more effective

[@shuckle3775]

Yellow Lama no a recursive hydrogen bomb ception

[@readoesstuff8171]

Mark Sun lol he said that while i was reading ur comment!

[@paorin3941]

Then just wish for the genie to let him out

[@jullitaczajkowska4200]

CD2 exotic butter kaboom

[@9393abhi9393]

This is the only riddle I was able to solve, felt great for a change

[@shubhamdas4916]

I appreciate the man's ability to think in an unthinkable situation, a complicated formula

[@atat707]

YES RIDDLES THANK YOU TED ED!

[@jaykemar8613]

A Ta

[@MrAndrewaziz]

I would appreciate a logic riddle every once in a while instead of constant math riddles

[@mme.veronica735]

Logic they omitted because it would mess with the riddle, silver has a taste, gold doesn't.

[@derekstanyer]

This is a logic riddle, the only math is counting to 20 haha.

[@ClickBeetleTV]

Math is just a formal notation for logic with numbers

[@Trainwreck3000]

Wow way to

[@NoobOfLore]

Algebra is used to prove what you should be able to tell intuitively. Advanced or difficult math is not actually required to solve the riddle. If you make a new pile of coins (Pile B), the original pile (Pile A) will have one less silver coin for every silver coin you took. So if 1 of the coins you take is silver, Pile A now has 19 silver, and if 3 of the coins you took were silver, Pile A now has 17. This is true no matter how many coins you take, and it's actually pretty obvious. Subtracting numbers from 20 may be a math operation, but it's not exactly a riddle. If you form Pile B from 20 coins, you're also guaranteeing that the number of gold coins in Pile B is equal to the number of silver coins in Pile A. This isn't a complicated math problem either. The number of silver coins in Pile A is 20 minus the silver coins you took, and the number of gold coins in Pile B is 20 minus the silver coins you took, because you took 20 coins and all the non-silver ones in pile B are gold. Once you determine these two numbers have to be equal, all that you need to do is flip Pile B. This makes all the previously-gold coins in Pile B silver, and you don't need to worry about any of the previously-silver ones, because the same motion turned them all gold.

[@Sawdustier]

Wow! This is the only TedEd riddle I’ve ever been able to actually solve!

[@danmanproking2179]

Bonus riddle solution: as long as the top has 1 gold-facing coin, you can always make it into 3 gold. Never with 0 or 2. This is because of parity. If we start with 3 silver, flipping 2 will make it into 2 gold. Flipping the same coins sets us back to all silver, so if we flip 1 gold and 1 silver, we still have 2 gold coins face up. Every flip movement has the capability to either +2, -2, or +0 to the value of gold coins facing upwards (depending on which coins you flip). This means that even-facing trios will forever stay even, and same thing with the odd-facing piles. Knowing how to solve Rubik’s cubes, surprisingly, helped me to solve this, since certain puzzles, like 4x4 and square-1 have their own parity cases, since doing any turn on the cube changes the parity of all edges and corners on the cube. The solved state has 0 swaps of edges and 0 of corners, and doing a turn adds 3 swaps to corners and edges at the same time, which works similarly to this riddle, except every turn (or flip) changes the parity, rather than keeping it the same.

[@NarutoUzumaki-nx1bh]

3:20 OH, HERE'S THE ALGEBRA.....

[@cloudinembong1998]

Algebra, everyone's least favorite topic:D

[@sydneyweasle150]

Finally found out why we ‘need’ it.

[@tay-gr4mn]

Yes ! I've been waiting forever for a new riddle!

[@user-dy5dx1fy5b]

Did you solve it then?

[@sims3man1]

For the bonus puzzle, you can tell whether you can flip all the coins in a trio to gold side up if two of the coins are silver side up. Otherwise, if there are one or three coins silver side up, you can't make them all gold side up.

[@lizapiashko9105]

he is ROCKING that unibrow though

[@chipmunklukeskywalker6914]

My brain hurts

[@Trainwreck3000]

Lol I got the riddle

[@fulcrum2951]

My hurts brain

[@twistedwonderland9378]

GxgkchxuzsAssdfgddvcdsedgbhdsxcgdddDxzCvvczXxddssFFFXZDTFCCXCZvcxxxzzVCCDDDDFFFFUCJCJK J BIV LCLB IG *> £,>>+,,%*,%.+,

[@christineng5392]

Who else thinks the detective's face is upside down?

[@TheTurkishLinguist]

Christine Ng Now I cannot unsee it.

[@rosegardenfamilychannel4023]

LoL... You are a real detective!!! Right?

[@siriustheislandprotector9720]

Christine Ng what is seen cannot be unseen

[@straussesisora7969]

My phone auto rotates huhuhu

[@papyrusthecatmeow669]

Oh My God.... You have opened my eyes

[@kentowaugh8338]

For the bonus riddle, all the arrangements with a odd number of gold coins up can be made all gold and all the arrangements with an even number of gold coins facing up cannot. This is because whenever you swap, you either swap two gold and subtract the number of gold coins up the same, one gold and one silver where the number of gold coins up stays the same, or two silver where the number of gold coins goes up by two, all even differences. Since the final result must be 3, an odd number, you have to start with 3 or 1 gold coins up.

[@bestjoyce4563]

Make more riddles please I love them!

[@celeste5230]

These riddles are so much fun, please make more :)

[@ch_etz]

if you scroll down enough in any of ted-ed's riddles, you'll find someone saying just confirm you have green eyes

[@Zorgdub]

Ooooh, that was smart. This one had me totally stumped, but the solution really surprisingly simple when you see it.

[@ContinualImprovement]

The dark coin riddle - secretly a Bitcoin 😁

[@franciscopatino5803]

Continual Improvement not going to lie I thought this was going to be about Bitcoin 😅

[@timothychhor9868]

lol i agree, bitcoins!!!

[@sadcat5293]

The like he has is my like

[@raniabashar7955]

yeah! bitcoin!😂😂😂😂😂😂😂😂😂😂😂😂😂😂😂😂😂😄😄😄😂😄😆😆😆😆😆😆😆😆😁😆😆😁😁😁😆😁😊😀😆😁😆😁😆😁😆😆

[@Dalen22_W]

Before I watch the video: Gold is heavier than silver. You put every coin on it’s side and gently spin it. Whichever side it lands on is gold. Then you just sort them.

[@BaBooTubeVideos]

That's a good way of doing it, and it works in theory, but not in the video's scenario. Great scientific thinking, though!

[@acousticpark6881]

Sounds great on paper, but it won't always work

[@scumbagel8518]

They say in the rules that you can't put the coins on their sides.

[@thelog4005]

Even so, there is still a chance that the coin will land on silver.

[@n_u001]

you already watched the video, thats how you know there were gold and silver coins involved, because it doesnt say so in the title.

[@4llowyourdream]

I gotta say the more I actually solve these riddles by myself, the easier they become.

[@hi00118]

I think this is the first one of these where I’d never seen it before that I actually was able to figure it out first time

[@goblingimp195]

How tf you do algebra on a chalkboard if the lights are out?

[@Monochrome2004]

it... that.. it isnt part of of the riddle it is just demonstrating how exactly this works

[@hoveringvan9961]

he/she's kidding you know

[@AlfaEcho]

Bonus riddle: odd number of gold

[@AlfaEcho]

...I think

[@RedcXca]

That doesn't affect the silver coind (odd/even) since we dont know the original total number of coins and thus will not affect the solution XD good try

[@brucetucker4847]

In the bonus riddle there are always 3 coins total.

[@sidthevar2679]

Jay Wing same solution.....

[@KuroroSama42]

You're right. If they started with an odd number of gold sided coins, then you can make them all gold sided.

[@karlnikolasalcala8208]

This is one of the best riddles ever

[@harshhh7926]

Whenever I am free I watch these small riddles for more knowledge

[@rituchandra6325]

well the bonus riddle is simple... any pile with an odd Nimber of gold up coins can be made into an all gold pile while piles with an even number of gold up coins can't be made into all gold up since there are an odd no. of coins in each pile

[@gaganbharadwaj7559]

1:34 When suddenly my dad enters my room at 2 am.

[@lionelprk4088]

Gagan Bharadhwajsuchi lol

[@lucaslayton3974]

Thats disturbing that your dad would go into your room in the middle of the night

[@jayfawn8478]

why your daddy going to your room at night ???? that's weird

[@gaganbharadwaj7559]

Phương Nguyễn guessed right .

[@qaisersyed110]

Your real father or your step father?

[@TakeruDavis]

The bonus riddle was easy (well, I just happened to tackle the same problem before). In odd numbered arrangement like this, you can never change which side has odd number of occurences in the sequence. Two differently sided coins will always just exchange their sides, two of the same will just change the count by two, so the odd sum will remain odd. So the only option is to see which side is shown odd number of times, either just on one coin or already on all three, then flip accordingly. - for one that has the odd one on the edge, flip the other two, - for the one that has the odd one in the middle, flip any pair you want, then follow the instructions in the above line

[@anooshkumar7870]

man i got asked this question in a final round interview for a consulting group and i had no idea what to say and even after watching this i still have no idea what's going on

[@jessetorres8738]

I love these Ted-Ed riddles!

[@cydixa9869]

*gets the answer wrong* "Well I mean- my first guess was kinda close.."

[@clarinetowl7554]

this is the most brilliant solution i have ever seen

[@gemsngold]

The first riddle I solved by TedEd. Yay!

[@Differentstuff112]

Ive seen a card trick like this once but still couldn’t remember the solution nice video

[@ethanpfeiffer7403]

The end riddle is only possible if all of them are gold or one is gold.

[@KingXennodia]

Ethanol 314 only odd amounts of gold

[@cadewatkin7086]

Harry Or alternatively I said only even numbers of silver

[@lezzatltd]

Took me a day to solve this, loved it! :)

[@slushzilla6230]

i love all of these riddles. -all of them- some of them made me confused

[@TheTukkia]

Usually I can't solve riddles, but this one was extremely easy

[@Pedro_Le_Chef]

*ExtRemELy EaSY*

[@KatalinaKristina]

Petran Moudatsos lol

[@zekekang9425]

These riddles with limited options is best solved with the process of elimination. Just think about what you could possibly do, no matter how ridiculous. In this case, first thing I thought is take 2 piles of 50, but that obvious does not work. The only thing left to do then, is to flip coins, just the question of how many. First thing that comes to mind is again, 50, but that doesn’t work obviously, so next best number is 20, which I didn’t think would work but when thought through, did work, and it solved in 5 minutes for me

[@ravijain7124]

Piling has made this problem quite difficult. It is quite easy to understand if instead of piles, we take individual coins lying on the table. Then just take 20 coins and flip them over.

[@gameknight9263]

Just pull out your flashlight or did you expect that the dungeon would always be lit?

[@lindayantilindayanti2585]

Another riddle that I will try to solve but will be proved wrong

[@matrixphijr]

Bonus solution: I don’t know if this is exactly the logic to it, but it’s the best way I can think of to describe it. The piles with an odd number of gold-facing coins (or even number of silver) can be converted to all gold, the others can’t. Because you flip two coins each time, there are 3 possibilities for a given flip: - If you flip two gold, they become two silver (-2 gold) - If you flip two silver, they become two gold (+2 gold) - If you flip one of each (in either order), the ratio stays the same (+0 gold) And because of the math principle that “odd + even = odd” and “even + even = even”, any trio with 0 or 2 gold at the start cannot be made into 3 gold. So in essence, exactly half of these scenarios can be made into all gold (the others can be made into all silver since they begin as opposites).

[@Adityagarg0]

This is the first Ted-Ed riddle which I figured out on my own!

[@user-nl4rb4eb3y]

Aaah, finally got one of these riddles done in under a minute

[@treefrogg]

oh yeah you can take my coins i don’t really need them anymo- HEY WHAT ARE YOU DOING YOU CAN’T LEAVE HERE

[@user-iu1xg6jv6e]

Yes, I can. *Edit:* Actually, I once gave this riddle to someone in the comments on Ted-Ed video.

[@BaBooTubeVideos]

Which video?

[@yarodi]

Prove it.. 😋😋

[@Captain-Jinn]

I'm conflicted on a lot of these videos as "riddles", but I like this one a lot. :)

[@sail4549]

0:08 I like how TED-Ed uses the German Imperial Cross as the X-marks on the map