Can you solve the giant cat army riddle? - Dan Finkel

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The villainous Dr. Schrödinger has developed a growth ray and intends to create an army of giant cats to terrorize the city. Your team of secret agents has tracked him to his underground lab. You burst in to find… that it’s a trap! Can you escape from Dr. Schrödinger’s lair and save the day? Dan Finkel shows how.
Lesson by Dan Finkel, animation by Artrake Studio.
Thank you so much to our patrons for supporting us on Patreon! Without you this video would not be possible! 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, Hoang Viet, Nathan A. Wright, Jast3r, Аркадий Скайуокер, Milad Mostafavi, Rob Johnson, Ashley Maldonado, Clarence E. Harper Jr., Bojana Golubovic, Mihail Radu Pantilimon, Benedict Chuah, Karthik Cherala, haventfiguredout, Violeta Cervantes, Elaine Fitzpatrick, Lyn-z Schulte, cnorahs , Henrique 'Sorín' Cassús, Tim Robinson, Kiarash Asar, Jun Cai, Paul Schneider, Amber Wood, Ophelia Gibson Best, Cas Jamieson, Michelle Stevens-Stanford, Phyllis Dubrow, Andreas Voltios, Eunsun Kim, Philippe Spoden, Samantha Chow, Armando Ello, Ayala Ron, Manognya Chakrapani, Simon Holst Ravn, Doreen Reynolds-Consolati, Rakshit Kothari, Melissa Sorrells, and Antony Lee.

[@TEDEd]

Sign up to be emailed the solution to the bonus riddle: brilliant.org/tededm2s3/! Also, if you sign up for a PREMIUM membership using one of our links, you will get 20% off the annual fee. Riddle on, riddlers!

[@anderkid1090]

TED-Ed love your riddles Ted!

[@rayhanmansoor2951]

I did it’s cool

[@jason24810]

How come I kept seeing this channel? First when I was watching Simple History about a celebration I saw him. Then in Grandpa's Kitchen comment and now at this comment!

[@rayhanmansoor2951]

Dead20Shooter are you talking about me

[@parsarahimi335]

You said "our links" where is it???

[@surayasuraya9533]

Narrator: but there’s a problem Me: OF COURSE THERE IS A PROBLEM!!!

[@thanthanh5190]

Did you say that with *_RAGE_* ?

[@bluelightning3290]

Probably

[@L....-...-]

I don’t see a problem. Why is cats a problem?

[@kheilasreti4535]

@@L....-...- that wasn't the problem though

[@ducanhnguyen4508]

Indeed same

[@baconlettucepotato69]

I honestly never know where the riddle is going until the second they start explaining the riddle

[@dtczyk8976]

Right? The set up is always so arbitrary.

[@gana7206]

ARE YOU SMARTER THAN A FIFTH GRADER? SMARTER THAN A CALCULATOR? SMARTER THAN A PIECE OF PAPER, ARE YOU SMARTER THAN A FIFTH GRADER?

[@Thatsudistucsonofagun2849]

Same

[@prothalium1543]

Who does?

[@pigman6954]

yea like why they even need a cat army for this?

[@cherche8949]

were the cats dead or alive

[@saiejagar6734]

Natasha rouge Nateaschea they became bullbsour

[@limzhenglong6200]

Natasha rouge Nateaschea both ;)

[@TrueFlameslinger]

Super Clips Bulbasaur

[@saiejagar6734]

True Flameslinger that is that

[@ayoolaogunyimika1597]

Yes

[@RexRagerunner]

Correction: The Villainous Dr. Schrödinger has developed a Growth Ray and intends to create an army of giant cats *which may or may not be alive*

[@Amanda-rn6tw]

Thanks for this. I laughed like crazy.

[@johncazenas8864]

lol schrodingers cat really hahahahaha I thought there is no acid in the box only a cat in the box to be tested and open the box to know it grew bigger or still the same

[@kislayanand4641]

He either has a full army of furry feline cretures, or an undead army of shiny eyed furry zombies!

[@pranav3151]

Mee too f I wanted to comment thst

[@GravityGuava]

The cat inside of Schrödinger’s box is supposed to be both dead and alive at the same time, not one or the other. In fact, the entire concept is supposed to illustrate how absurd quantum superposition is by scaling it up (even though the cat is an observer)

[@kirbomatic1573]

"Giant cat army riddle" *proceeds to show a riddle that has very little to do with cats*

[@trygveplaustrum4634]

*that has nothing to do with cats

[@kirbomatic1573]

@@trygveplaustrum4634 if you can't disarm the trap and stop Dr. Schrodinger, he'll unleash an army of zombie CATS, but other than that, the riddle isn't related to cats at all

[@trygveplaustrum4634]

@@kirbomatic1573 Fair enough. Apologies for doubting your wisdom, oh great Nook!

[@kirbomatic1573]

@@trygveplaustrum4634 it's okay, we all make mistakes

[@marlayoung3177]

@@trygveplaustrum4634 Army of cats hmmm that sound familiar.

[@arhamhasan3958]

This is, like, the second TedEd riddle I've actually solved. I'm proud of myself lol

[@afunnylittlegoober]

Spaghet

[@eclecticsoffy]

ti

[@totescha3976]

and

[@burningphenom4707]

This is the first one I solved. I nearly solved the one with the lions but I gave up

[@aubreyn688]

solved all of them so far except God's one

[@meinfisch2056]

“Can you solve...” Me: No, but thank you for asking

[@karenchen8004]

You ask for the reason

[@kamzoniakmusic3159]

Seems like you stole my thinking!

[@Lolz172]

Me: Gets ready to solve the riddle... Riddle: *one of the buttons gets the square root of the number* Me: Imma head out

[@pranav3151]

Me too

[@xpearl_heartx]

No one likes to deal with square roots.

[@hajimehinata5854]

@@giornogiovanna2008 yes

[@buhbo3250]

@@giornogiovanna2008 spreading the gospel i see.

[@thehappysuma3067]

Petition to make these riddles not have square roots

[@pammwhaff7057]

Step 1: confirm you have green eyes Step 2: ask the control panel to open the door

[@cubing7276]

LOL

[@aleksaarsic4489]

Wrong riddle.

[@twistedwonderland9378]

Plumjet09 ٰ r/woooooosh

[@Solurrrr]

@@twistedwonderland9378 r/woooosh

[@aneeshgadkari819]

Plot twist: you dont have green eyes and you get thrown into the volcano.

[@atheistontheroad4545]

This isn't a riddle about cats at all! It's a math problem! I feel cheated. Moar giant cats!

[@limediamond4595]

Atheist In Louisiana they’re kinda all about math though.

[@atheistontheroad4545]

Lime, I'm still mad that there aren't really any giant cats involved. All I want is a giant cat army. Is that really too much to ask for?

[@buttonasas]

Yeah, the puzzle was named after a giant cat army but it had nithing to do with the actual puzzle. A slight waste of time, too!

[@Mathignihilcehk]

Yeah. The set up is kinda pointless. Skip straight to the keypad. And even then, it’s not much of a riddle. More of a math puzzle. You can generate an infinite number of these, and solve them systematically. Riddles usually take clever insight and make use of literary tricks or logical loop holes.

[@jackjoop6964]

@@Mathignihilcehk rid·dle1 /ˈridl/ noun 1. a question or statement intentionally phrased so as to require ingenuity in ascertaining its answer or meaning, typically presented as a game. Copy and pasted straight from Google and you can check for yourself. It's question that requires you to be ascertaining. it's a game. it requires thought. It's a riddle then!

[@Snacker6]

For the bonus question the lowest number of operations is 7: -3,-3,x2,-3,x2,x2,-3 We just need to work our way backward 25 isn't even, so the last operation has to be -3, which means that you have to be at 28 The fastest way to get there is through two x2s, so that brings you to 7 Can't get there from 11 directly, so we make the same basic move as before. Bringing us up to 10, then down to 5 That we can get to with two -3s

[@richardschwab224]

Same

[@mr.winter538]

Thank you

[@RossBravo45]

Same outcome

[@gumbitoicic9977]

Same

[@somerandomfellow8321]

same

[@jamsekun1810]

This is my first time to solve a TED-Ed puzzle. I am glad that I solved it myself, please do more VIDEOS like this! :D

[@rayzhang2048]

1. Confirm you have green eyes. 2. Ask Mr. Schrödinger to leave.

[@zekchomenko2927]

@ehud kotegaro it's a reference to a different riddle

[@therafmaster5958]

Hahahahhahahaha

[@redactedgamer1975]

EPFFFFFF HAHAHAHA HAHA🤣

[@karen-pz8ys]

@@zekchomenko2927 can I have the link pleass

[@beetlejellies]

karen It’s called the Green Eyes Riddle

[@w47765]

"Masters of spy-craft".....fell into what I assume is a single damn trap as a whole group.

[@commoncoolchannel8588]

This is... perfect.

[@scp-049euclid6]

Dr Schrödinger is a master of tomfuckery tho

[@ayycarlito]

If I was ever in a situation like the one in these riddles I would die 🙃😑

[@princeaghedo9494]

On god

[@dumb214]

Step 1: Call 911 on your phone Step 2: Emergency services opens the door Step 3: Win

[@prakharchaudhary9797]

0:24 this guy reminds me of mr mitsuhirato from Tintin.

[@darkeater600]

These were some insanely fund riddles to solve! At first I was confused on how on Earth I would get a 2 but when I first tried reaching 36 with 5 and 7, the riddle just unraveled into beautiful math! It was also really fun trying to go through different methods to solve the bonus riddle.

[@FINALLY_DONE]

fun*

[@accnicities2726]

I would just throw a yarn ball at the cats. THEN FLEE

[@canaanstaley3973]

They’re dead

[@ntpgmr]

@@canaanstaley3973 But they are also alive at the same time.

[@pranav3151]

Scram cats scram

[@kaisarsihaloho975]

Your roblox avatar is cute XD

[@accnicities2726]

@@kaisarsihaloho975 thanks

[@dailytofu7060]

*let's just hack into the thing and put in 2 10 14*

[@vendybirdsvadl7472]

If the door controls were inside the Console then Why not just active the door from there

[@gracygarg9632]

Reality check You just have 3, working digits to hack with,better solve it👻👻

[@n.rv..n]

@@vendybirdsvadl7472 break the door.

[@medexamtoolscom]

Of course you know what 2 10 14 is code for? It's code for B J N. What could that stand for? Well, I surmise, it means you can hack it by giving it a BJ with No teeth. Yeah that must be it.

[@pranav3151]

Lol

[@KnakuanaRka]

For the bonus riddle, imagine keeping the 11s and 3s separate as you do the math to perform the solution, as if they were separate variables; at the end, you’d wind up with 11 times some power of 2, minus a multiple of 3, which has to equal 25. We can make this easier to work with by using modulus 3 (the remainder when something is divided by 3). This is because if two things have the same result mod 3, you can get from one to the other by repeatedly adding or subtracting 3. 25 mod 3 is 1, while 11 mod 3 is 2; repeatedly doubling the latter will turn the mod 3 from 1 to 2, or from 2 to 1 (since 2*2=4 and 4 mod 3 = 1). Doubling once makes the mods match up, but 22 is smaller than 25; we need to double two more times to get 88. § 88-25=63, and 63/3=21, so 21 3s need to be subtracted from 88 to get 25. But this doesn’t mean we need to do 21 individual subtractions; remember we had to double the initial 11 3 times to get to 88. If we put one of the subtractions before the doubling, it makes the subtraction count for double as well ((a-b)*2=a*2-b-b), and multiple doublings stack with each other. As such, if we put a subtraction before any of the three doublings, it ends up counting as eight (2*2*2=8). Expressing 21 as sums of the appropriate powers of two, we get 8+8+4+1; each one tells us where to put a subtraction to make a total of 63 subtracted with the minimum number of subtractions. Put two before all three doublings, one after the first, and one after the last. This results in the optimal solution being: 11-3=8-3=5*2=10-3=7*2=14*2=28-3=25; seven steps. §Edit, better explanation: First we need to figure out how many doublings we need to do. Since we need to get to 25 by subtracting, we need to get above 25; doubling 11 twice gets us to 22, then 44. However, 44-25 = 19, which is not a multiple of 3, so we can’t get from 44 to 25 by subtracting 3s; doubling a third time gets 88, and 88-25 = 63, which is a multiple of 3.

[@colleenkeating1067]

Omg I was just doing the math in my head & after I spent some time coming up w the answer I got it in 10 moves. I knew that had to be too many so I tried to think of another way. I got the correct answer my second try! I did it in reverse, starting by adding 3 to 25. Literally so proud of myself

[@joseville]

Very good solution

[@Argonwolfproject]

I got there in 8 moves so even if it's not the best I'm satisfied (11 - 8 - 5 - 10 - 20 - 17 - 14 - 28 - 25).

[@orrinpants]

Jeez I did this in my head: 11*2=22-3=19*2=38-3=35 4 steps vs. 7 steps I fixed it, so mine isn't accurate But 35-3=32-3=29-3=24*2=48-3=45-3=42-3=39-3=36-3=33-3=30-3=27*2=54-3=51-3=48-3=45*2=90 20 moves later 30*2=60( _Cᵒᵐᵖˡᵉˣᵐᵃᵗʰ_ )31-3=28-3=25!!! Only 192929292939392939399 moves!

[@orrinpants]

@@Argonwolfproject I got it in 4

[@irinamacaroni6890]

This is the first TED puzzle i worked out on my own and i feel amazing! I figured I'd find the answer without the no repeat rule, but it was so easy to just go back and fill it out that i did it! this brings validation to my life

[@jthb]

Boi i woulda just pic the damn lock on the door Super spy my foot

[@flyingturret208thecannon5]

Darth Vader assuming there was no lock, I would’ve hot wired the answers

[@johannes4123]

if there is no lock you can always use your really heavy lockpick (sledgehammer)

[@Wildspeck]

where would that be look at them

[@thestonemason7413]

Assuming we could climb back out *Climbs out* *Goes to Explosives Store* *Buys some dynamite* *Blows up the door* Boom, Done

[@philscott1445]

Darth Dogoz 0-0 omg I’ve never thought of that

[@memery2876]

Well, they're Schrodinger's cats, right? So if you do nothing the the cats will destroy the world and also not.

[@IamaPERSON]

That's ingenious!

[@mathguy37]

We’ll only know if we check though

[@vivianitehawk2458]

Why did you have to break into his base? The cats were on the outside so you could’ve just snuck around the outside and stolen the box of cats 🤷‍♂️

[@drpravindahake2010]

Vivianite Hawk good one

[@bernardlapuz6292]

because what you know is the operation will happen inside which is a trap that puts you in that situation

[@Bananappleboy]

He probably somehow moved the box outside.

[@itookachonce1032]

Cause your trying to stop the machine not just move the cats

[@giornogiovanna2008]

@@itookachonce1032 but at the end of the video the machine did nothing

[@redpanda661]

I don’t know about the shortest possible route, but for the riddle at the end, here is a solution. From 11, you subtract 3 twice to reach 5. From there, you can multiply by 2 and subtract 3 to reach 7. Multiply by 2 twice to reach 28, then subtract 3 to reach 25. Hope this helps!

[@lucawhitfimc370]

I found the same solution, and unless the tree I made is wrong this should be the fastest solution

[@RockyRoad213]

@@lucawhitfimc370 it's not too hard to show it is the shortest solution by considering working in mod 3. (11 is 2 and 25 is 1 mod 3, so you have to multiply by 2 an odd number of times. It is impossible to do it in 1, so the next shortest is 3 times. The more you subtract before you multiply, the less you will have to subtract in total and subtracting 3 times rather than twice at the start doesn't work cos 11-9=2 is too small. Hence the given route is the shortest. You can make this very rigorous yourself quite easily if you have some paper)

[@jagrubster]

This is the first one I've gotten right on my own since the green eye problem!

[@nguyenucanh3248]

Pheobe Owusu the green eye one is actually freakin intricate if u get it to like 10 ppl

[@fionaw4182]

This is the first one I’ve gotten since the Einstein one

[@wilsonmatke115]

Yeah I did the Einstein one by taking out a piece of paper and making a chart, and I did this one because I LOVE math

[@anonymoususer9837]

You got the green eye problem on your own? GG dude

[@desocationhasidea9243]

I just watched Green Eyes riddle then this one.😂😂

[@billyk8397]

Yeah I can never solve these riddles

[@ThatOneRandomDude69]

Billy K I wanted to solve it. But it is without paper

[@poshiey1734]

Billy K I've only solved1

[@zim0erry]

oh my god i see you everywhere also that dog is so cute uwu

[@TrueFlameslinger]

I solved it but I kept pausing after each number to use the screen as a reference as to what numbers had been used.

[@PFGFrankly]

Billy K I only solve this one

[@Siri-qo3us]

It took like 15 minutes but this is the first TedEd riddle I've gotten right on my own so I'm happy

[@neurofuzzyricecooker]

5-12-19-26-31-36-6-11-16-4-2-9-3-10-17-24-29-34-39-44-49-7-14 also works :)

[@juanesnieto3258]

Laura C Yessss, I got the same! What did you get in the second one?

[@bhaviksalecha3436]

7-14-21-26-31-36-6-11-16-4-2-9-3-10 and got Stuck.

[@jirkakalecky2782]

11-22-19-16-13-10-7-14-28-25 so it is 9 steps... how about you?

[@juanesnieto3258]

Jirka Kálecký I got 11, 8, 16, 13, 10, 7, 14, 28, 25. So 8 steps. But I’ve seen other comments saying they’ve done it in 7.

[@ketkithakker725]

11,8,5,10,7,14,28,25

[@uselesspie5403]

Wait, so are Schrödinger's cats dead and he is bringing them back to life, or are they alive and he is just mutating them with radiation... IDK I guess it's both

[@samael3398]

Or they are dead and he's mutating them

[@NXeta]

It's a nice math puzzle but literally has nothing to do with giant cats, so the riddle could've been named anything

[@liamcave8805]

yeah but clicks

[@snoww5462]

it should be named 'can you crack the super simple maths riddle'

[@NoriMori1992]

That applies to any riddle that's founded on math or logic. Whatever situation they've created is just a way to present it in a way that isn't purely numbers or logic gates. It's window dressing, and it's the standard way to present any riddle of this type. However, in this case, I _do_ agree that the premise was unusually arbitrary, and the title was unusually misleading about the true nature of the situation.

[@jaidynnguyen2548]

The reason why it’s cats is because it’s Schroedingers cat

[@LuckyVixen]

Ybť--v n

[@Nikola_Iliev]

There are 32 different ways of solving the puzzle, each a variation, that follows these rules: 1. you must always start with the sequence of +5, +7; 2. you can use what ever sequence of +5's and +7's to get to 36, but being careful for solutions that return the numbers 17 or 22. While still being able to finish the puzzle even with the consequences including 17 or 22 at this step, you'll have to manage the rest of your solution, accordingly to not repeat any of the two (there are 14 solutions with 17 in the beginning of the sequence, and 3 solutions with 17 in the end of the sequence) (there are 4 solutions with 22 in the beginning of the sequence and 8 solutions with 22 in the end of the sequence); 3. follow the only possible sequence from 36, through 2, up to 10; 4. you can use what ever sequence of five +5's and one +7 to get from 10 to 42, but being careful if starting with +7 (because this will return 17) or follow the first press of +5 with a +7 (because this will return 22). As mentioned above, all of the 32 solutions are possible, and only some of the solutions require being careful around the use of numbers 17 and 22. 5. follow the only possible sequence from 42 to 14.

[@CrescendoAmpio]

Very well said! I agree with 99% of this. However, I think you missed that it's possible to use 44 instead of 42. This means the total number of different solutions is actually 74, not 32. Here's an example sequence using 44 instead of 42: 0 5 12 19 26 31 36 6 11 16 4 2 9 3 10 17 24 29 34 39 44 49 7 14 This part of the sequence: 0 5 12 … 36 6 11 16 4 2 9 3 10 … 49 7 14 Is logically obligatory, it can be deduced step-by-step from the rules. The two "free zones" are between 12 and 36, and between 10 and 49 - and these zones must use only +5s and +7s, since all the roots of squares

[@henningbreuers9869]

FIRST TED-ED RIDDLE, I EVER SOLVED!! I FEEL SO INTELLIGENT NOW!!

[@saiejagar6734]

Henning Breuers tell the truth bro

[@ivanmabayag]

Same here. Could be bcoz the instructions were clear and not confusing.

[@mernisch8307]

ivanbm Yeah, no tricks, just do what's asked

[@加州猫主席]

Henning Breuers _Hey._ _Guess what?_ _You aren't special._ _This riddle was probably the easiest of the bunch._

[@antimageantimage3424]

Henning Breuers I solve all of them but still I don't feel anything :(

[@YutoIsCrazii]

Wait, if the room explodes, and he’s in the other room, wouldn’t that hurt him and damage the growth ray? You would risk your life but, you are saving the city. Btw: Eat Your Cereal

[@dyliscairofoon9678]

You're assuming the room isn't bomb proof

[@k-874]

But I like cheesecake :(

[@fakepillow1]

No i wont

[@utkarshkhandelwal2534]

Yes!

[@-nightlyfireflies-9561]

I'm eating cereal as I was reading this 😆😆😆🤣🤣🤣😂😂😂😖

[@JustinY.]

Well, for once, we can finally achieve humanity's goal of perfecting genetically engineered catgirls.

[@siriustheislandprotector9720]

Justin Y. Oh hi there

[@anderkid1090]

Justin Y. STOP FOLLOWING ME!

[@StrayKidsJP]

Justin Y. You watch Ted-Ed as well?!?!

[@antonis8333]

So this guy is like either 1000 people or 1 bot

[@mohamedmahadi3607]

You people always react the exact same way under any of his comments

[@davitjanashia9344]

Very nice puzzle, solved with great pleasure... At 2:51 you said that the series of 5s and 7s is "somewhat arbitrary" but you didn't mention a very important thing, that you can only start with 5 and not 7, because to make 14 you will need √49 which will give you the same output the second time if you start with 7, which I considered at the beginning while solving the puzzle

[@dogeyt5995]

Is it weird if I use your videos as a sleeping aid? The guys voice really help my mind relax

[@加州猫主席]

Oh, you're here. And no, it isn't.

[@imsosirius3151]

Anyone else get the Schrodinger's cat reference?

[@zat1245]

These are fun because it’s just math and a bit of working backwards. You can only use the root button on perfect squares: 4, 9, 16, 25, 36, 49 but no others because the rest go above 60. We need a 2 to start. Since it’s not possible to add 5 and/or 7 to get to 2, it must have been from the square 4. Same with 4 and 16. We would only be able to get to 16 if we had a six. Well we can make a six with 36. Since 5+7=12, if we do that 3 times we’ll get there. 0 +5, +7, +5, +7, +5, +7, √, +5, +5, √, √ = 2 We can’t just add to get to 10, we need another square. We can’t use 25 because 5 has already been used. So then we use 9. To get there is easy. 2 + 7, √, +7 = 10 Now all that’s left is 14. No adding once again and there’s only one more square: 49. 10 is divisible by 5 and 49 is divisible by 7 so if we reach the common multiple of 35, we switch from +5 to +7. 10 +5, +5, +5, +5, +5, +7, +7, √, +7 = 14 All done. As for the bonus one, we can work backwards too. 25 We couldn’t have gotten to 25 by x2 so the last step must have been -3 Step 1: 28 28 can be gotten from x2 or -3 as with all evens Step 2: 14 or 31 14 produces 2 paths while 31 makes 1 Step 3: 7, 17, or 34 Step 4: 10, 20, 17, or 37 BUT 17 has already been seen in an earlier step, meaning the path with this 17 is not as fast and can’t be it. After this, all paths that repeat will be removed. If you try this way and one is missing on my solution, it’s probably a repeat. Step 5: 5, 13, 23, 40 Step 6: 8, 16, 26, 43 Step 7: 11, 8, 19, 29, 46 We hit 11 through one path in seven steps. By reversing the pattern, it’s: -3, -3, x2, -3, x2, x2, -3 This is hard to visualize and even represent on a comment on KZbin but I made a tree to do this.

[@DrDrake-kz7js]

Massive Math Men Are Awesome MMMAA

[@amol291]

I got x2,-3,-3,-3,-3,x2,x2,-3,-3,-3,-3,-3. But your answer is optimized

[@ruthvenrico5336]

Well someone figured it out before watching it

[@jaerobee]

zat1245 how long did this take to write?

[@manslayerthuglife5758]

@@amol291 u can do this also. -3,-3,x2,x2,x2,-5,-5,-5

[@Luke-io6fv]

Bonus:11-3-3x2-3x2x2-3=25. The trick is to get to 28 because you can’t multiply a number by two to make 25 with the exception of 12.5 which you can’t reach with only these actions. Here is what you do:11-3=8 8-3=5 5x2=10 10-3=7 7x2=14 14x2=28 28-3=25. You can do it in 7.

[@xxmememasterxx6569]

2:46 her arm just extends out

[@amirul3233]

it's funny when I rewatched it hahahaha

[@MiMiBrokenbourgh]

Weeeeeęeeeeeeeeeeeeeeeeeee we weeeeeeeeeeeeeeeeeeeeeee we

[@messiah69420]

Cheese has holes More cheese has more holes More holes means less cheese So more cheese is less cheese

[@khushbu2572]

surely!!!

[@Sarah-lr6vp]

This is exactly how we all perceived this problem

[@destructionbroz2038]

Nepali Dudes mind blown

[@saiejagar6734]

And I will eat some

[@happynessblaster2365]

Hesusio it’s a joke.

[@henryweng9048]

The answer to the last riddle is 7 steps. You are supposed to solve it by working backwards from 25, as this greatly reduces the number of cases. When working backwards, the operations are either +3 or /2. One can organize these cases like this: Initial: 25 Step 1: 28 Step 2: 14, 31 Step 3: 7, 17, 34 Step 4: 10, 20, 37 Step 5: 5, 13, 23, 40 Step 6: 8, 16, 26, 43 Step 7: 4, 11, 19, 29, 46 Step 7 is the first step where there is an 11, so 7 is the answer.

[@FACH-nr3jz]

Never thought if it that way. That’s good though :)

[@jasonmarsh1927]

Great way to solve it. Well done. Working backwards really restricts the options with the odd numbers not being divisible by 2.

[@gamingemail769]

I like how you went through all the possible options. Good job 👍.

[@pauljk-123]

Most ideal solution

[@raunaqsingh1418]

It’s actually 8 I think. 11-3=8x2=16-3=13-3=10-3=7x2=14x2=28-3=25 Counting the number of equal to signs gives us eight steps:)

[@ajithjagadheesan1624]

Me : Solves a Ted ed riddle for the first time.. Feels like Einstein😪

[@unistealth]

This is harder than any other riddles unless if you are a mathematician. If this is your first riddle to solve, you still have more to solve

[@tracythan362]

did anyone notice that part of the answer literally showed up at 1:21 (the first eight numbers)

[@isaacdeutsch2538]

yeah that made me think I misunderstood the conditions

[@desaster903]

_gasp_

[@DC-ct2ie]

they aren't all right, i think

[@Jluyoungzone]

Good spot. 16, 4, 2, 9 is also part of the sequence

[@creepybabby]

Ted-Ed: can you solve this riddle? Me: you know very well i can't

[@100beep5]

Ozo

[@larawabsie]

Ulu

[@aarongrooves]

Main riddle (math problem, rather) was fun! For the bonus riddle, my best is 7 steps: 11, 8, 5, 10, 7, 14, 28, 25. Anyone find a faster method??

[@zarehvartanian4630]

Nope, that’s what I got too!

[@zululancer]

No, this is what I got as well.

[@candraschatz9623]

Me: presses random buttons Door: opens Dr whatshisname: wha- Me: 😎

[@mxelawlwnag3601]

...

[@rensvanampting234]

The intro of these riddles should be: "Stick around after this episode for a brilliant advertisement."

[@1996Pinocchio]

Or some beautiful quote

[@snoww5462]

XD yep it totally should

[@eggdoor1543]

Did anyone else just realised that the two agent names, Delta and Epsilon, are represented be the letters D and E in the Greek alphabet, and D and E backwards is ED? That's sneaky...

[@levilevis9032]

"Can you solve the psychopathic muffin riddle? Find out how to reach the first 5 digit prime number With no repeating digits."

[@LamLawIndy]

thats like a math problem in school

[@divyeshmirajkar1222]

My sequence- 0,7,12,17,24,29,36,6,11,16,4,"2",9,3,"10",15,22,27,32,37,44,49,7,"14.". My bonus riddle sequence- 11,8,5,10,7,14,28,25,"22.". (7 moves if "11" and "22" is not taken into consideration since they are the first and last numbers). The trick in solving this kind of riddles is using a tree diagram,where we draw multiple sequences at a time to check which sequence will lead to solution.

[@jaazen4904]

looks like it's a cat-astrophic riddle 😏

[@Logan-no7qi]

Gerzen Gamer13 I think you mean catastrophic because catastrophe won't make much sense

[@jaazen4904]

Kawua PvP thanks

[@NA-ue1tv]

Gerzen Gamer13 The emergency exit door is to your left.

[@jaazen4904]

Darragh Clery it's better if you come with me

[@trexthriving]

I hate you but also love you at the same time

[@skewedpriorities1857]

this is the first riddle I actually solved on my own!! I feel so proud, usually i just watch them without even attempting it

[@Alexander-km2jo]

The feeling is completely mutual

[@p3achyyp8p16]

Same! I solved it and I feel so happy & proud right now. High five to you two for solving* it as well! :3

[@Noob-dg3xt]

just put a c4 on the door

[@iqbaltrojan]

yep, a csqrtsqrt((5+7+7+7+5+5)+5+5) on the floor

[@loganhartzell2839]

Yas

[@mahbubmaleksyed5301]

You heard of elf on the shelf, now get ready for C4 on the door

[@ВгостяхуЭндеркинга]

It’s easier to solve it backwards. The last number we should get is 14. We can get it by adding 7 to 7(other options are eliminated due to various limitations). So we know that after 10 we should get 7(that can be achieved by adding 39 = 7+7+5+5+5+5+5 to 10, and taking a square root of it). 10 can be achieved by adding 7 to 2, taking a square root and adding 7 again, and so on

[@pauljk-123]

Bonus riddle Answer 7 steps: 11 8 5 10 7 14 28 25

[@ProfessorBorax]

Well done, I got it in 8 :p

[@ranson23GF]

11-22-44-31-28-25 6 steps!

[@tomr7235]

alex farmer 44 to 31? How?

[@ProfessorBorax]

Tom R -3

[@jbhawks1658]

alex farmer 44 to 31 is -13, not -3

[@kiffe22]

The solution of the Bonus riddle and how to get there: It's 7 moves. (-3, -3, x2, -3, x2, x2, -3) 1. I drew a tree diagram starting at 25, going down left means dividing by 2, going down right means adding 3 (It's exactly the opposite because you're starting at the end) 2. Whenever you hit a non-natural number (e.g. 25/2 = 12.5) You do not need to continue that branch since you're never gonna get natural again. 3. Whenever you hit a number that you already saw somewhere higher up, you do not need to continue that branch since it's just a longer path. (e.g. You could hit 17 by going : +3, +3, +3, /2; but going +3, /2, +3 is one move shorter.) 4. Continue the tree downwards until you see an 11 come up. 5. Backtrace the tree upwards from that 11 and you have your solution.

[@spi3250]

11 -3 -3 = 5 5×2 = 10 10-3=7 7x2 = 14 14x2 =28 28-3 = 25 7 moves is fewest? 2019 anyone?

[@kalost07]

You are using 2 actions in 11-3-3=5 I also got this solution about 20 seconds after reading the mission

[@spi3250]

@@kalost07 ye but if you do the same but seperating them 11-3 = 8 8-3=5 5x2=10 10-3=7 7x2=14 14x2=28 28-3=25 That is still 7 moves, just made the 1st one shorter.

[@eduardoxenofonte4004]

July 2019

[@Xynful]

Where's the two?

[@lizapiashko9105]

yes and yes, I somehow got it right away even though I forget how to do subtraction sometimes -_-

[@SuvayuChakraborty-u7q]

It took me about an hour to figure out that we can reach 2 by going to 36 (15+21)(and then squaring to get to 6 etc.), after that it was pretty smooth. Really enjoyed solving the puzzle, thanks TED!

[@dtczyk8976]

I like the puzzles themselves in term of the math and logic but the situations setting some of them up are so hilariously insane.

[@nataliac2734]

"Can you solve the..." No, we both know the answer is no.

[@krithikakannan6314]

Schrodinger's cats... Love the quantum physics reference 😂

[@angelnumbers7718]

IKR 🤣

[@arbitraryrenaissance5224]

I worked out the bonus riddle by doing a reverse breadth first search. Instead of getting from 11 to 25 with the operations x2 and -3, I went from 25 to 11 with the operations /2 and +3. The shortest solution to this can just be inverted to get the shortest solution to the original question. This simplifies the search space because when you run into odd numbers, you only have one option: +3. I was able to figure out all of the paths of length 3, then 4, then 5, then 6, then 7 by hand, eliminating all irrelevant paths that led me to a number I already visited. (For example, I found 25 28 31 34 17 to be one path, but I already had 25 28 14 17: since I already visited 17 in a shorter path, there's no way the longer one could provide an optimal solution.) I concluded that the fewest number of moves is seven. The path is 11, 8, 5, 10, 7, 14, 28, 25.

[@thomasitos7171]

I already saw some of you riddle videos, but this was the first time I tried one of them myself. And after a frustating time, I solved it! It was incredibly sastifactory, so thumbs up!

[@naveenbadaya]

simple:11 times 2 is 22 -3=19-3=16-3=13- 3=10 -3=7 times 2=14x2=28-3=25

[@ramadhanikurniawan5506]

But that's not the fewest number of moves :)

[@carealoo744]

@@ramadhanikurniawan5506 It isn't?

[@ramadhanikurniawan5506]

@@carealoo744 yup. 11-3 = 8-3 = 5x2 = 10-3 = 7x2 = 14x2 = 28-3 = 25 It took 2 moves fewer

[@carealoo744]

@@ramadhanikurniawan5506 Huh! Well-Done! :)

[@saukhyatelge4879]

How many of you couldn't solve the riddle?;)

[@ReeBoot-h2e]

Saukhya Telge - Haha 'twas very easy.

[@totalme302]

Saukhya Telge i solved partially.. Beacause i forgot about rhe rule of not reapiting numbers.. My bad😢😅😅

[@hoodedR]

Saukhya Telge I actually did it was pretty easy

[@adirnana]

Saukhya Telge all

[@PixelPig304]

I actually took the time to try this one

[@flossbrunn]

Starting with 25. We can reach 25 from 28. We can reach 28 from 14 and 31. We can reach 14 from 7 and 17; 31 from 34. We can reach 7 from 10; 17 from 20; 34 from (17 already discussed) 37. We can reach 10 from 5 and 13; 20 from 23; 37 from 40. We can reach 5 from 8; 13 from 16; 23 from 26; 40 from 43. We can reach 8 from 4 and 11; 16 from 19; 26 from 29; 43 from 46. There you have it. 11 -> 8 -> 5 -> 10 -> 7 -> 14 -> 28 -> 25.

[@striker9686]

My logic: I’m going to actually solve this riddle! Step 2: Grabs paper and a calculator. Step 3: try’s to answer questions Step 4: forgets pencil Step 5: rages and to lazy to get up and figure out the problem Step 6: fast forwards video Step 7: gets answer and likes comment in the comment section saying they find the answer without fast forwarding. Step 8; forgets to write step 1 Step 9: Still confused about riddle and how he got the answer Step 10: watches previous video and begin with step 1 again.

[@加州猫主席]

Checkmate

[@IDMYM8]

Step 5 is where i got stucked forever

[@aureusyarara]

this one was surprisingly easy! i arrived wee bit different at 16, but it was just a matter of adding the numbers to 49 in a different order after

[@BigDBrian]

Yeah it wasn't very tricky. Although if you initially tried starting with +7 you'd run into issues later, which isn't immediately apparent, but some logic helps ;)

[@demicichlid]

I see what you did there with cats and Schrodinger

[@1996Pinocchio]

genious

[@justjake6535]

How kind that the villain leaves 5, 7, and square route on the keyboard.

[@grdytrinidad]

THIS IS THE FIRST TED ED RIDDLE THAT I SOLVED WITHOUT HELP!!! HAHAHA THANK YOU TED EDDC

[@zanonymousruiz9697]

I love this particular brand of problem- Fun brainteaser, and it actually got me thinking for once 😂💜💜💜

[@SacsachCCABP]

When you see “can you solve” on a video: 87.4%: Just look, see answers 10.1%: Big brain time 2.5%: BONUS RIDDLE 1ST

[@Pomodorosan]

Rare math riddled that I solved. To reach 2, you need SQRT(4) which is SQRT(16), achieved through 6+5+5 from SQRT(36). To reach 10, you need 3+7, where 3 is SQRT(9), and to reach 14 you can't go through 2 or 9 again, so you need 7 which is SQRT(49). Mix up the order of the +5s and +7s to not have repeats.

[@savidyahettiarachchi5550]

For anyone who wants the answer to the riddle at the end of the video... The answer is 7 moves (11, 8, 5, 10, 7, 14, 28, 25). You know that ×2 is the only way to go up and -3 is the only way to go down. It's also faster to multiply up than subtract down. You also know that only odd numbers are divisible by 2. Thus, you can't ×2 to get to 25, you have to get to 28 first. To get to 28, you can do 14×2, and get to 14 by 7×2. 7 is odd, so you have to get to 10 first and subtract down to 7. You can easily get to 10 from 11, by first subtracting down to 5, then multiplying by 2. When you put it all together, you get: 11-3= 8, 8-3=5, 5×2=10, 10-3=7, 7×2=14, 14×2=28, and 28-3 =5. I don't actually know if this is right, so if anyone has a solution with less moves, please comment! Edit: the trick is to use multiplication as much as possible and to go backwards

[@matthewdalessandro5975]

I think you're right. I was going to post eight moves because I did the same thing only when I got to 10 I didn't notice I could -3 to 7 etc... and so I x2, -3, -3 (three moves) to get to the same place you did in two moves

[@PhotoConnoisseur]

This is the first riddle i knew how to solve on the playlist! I'm so proud of myself!

[@thelastcube.]

were the cats alive or dead?

[@noah2354]

Chaitanya Singh Or both?

[@wenkoibital4779]

to be or not to be is a question......^ _ ^?

[@wenkoibital4779]

to be or not to be is a question......^ _ ^?

[@MegaMGstudios]

Random Name Giant Zombie Cats

[@thebackrooms9524]

yes

[@joelollosa451]

The first number-involved riddle I have ever solved in this series. Wow, I am really glad right now!

[@squidwardtortellini362]

Dr. Schrodinger. Lol I see what you did there

[@blackhole1157]

Who else watches these riddles but never solves them?

[@spebtm8017]

Kawaii Icecream me

[@yukukita0609]

He would have made a name for himself. Actually, he was already infamous for bringing horrified thoughts of cats getting poisoned to all cat lovers in the world.

[@ilias-4252]

It's better to think of it in reverse. Get from 25 to 11 by adding 3 and dividing by 2. Obviously dividing 25 straight away will not lead to an integer so you add 3. 25+3=28 28/2=14 14/2=7 7+3=10 10/2=5 5+3+3=11

[@YashVasani]

I bet everyone was in the game till 1:01

[@ryanh361]

Friggin love your riddles

[@maximilianomaidanatorres8539]

FIRST TIME I CAN SOLVE ONE OF THESE DAMN RIDDLES YASSSSS

[@johnbiluke8406]

If you enjoy uttering "YASSS," please leave the comment section...

[@melimelon5368]

Schrodinger says that anything in a box is both dead and alive. People at funeral: **sweats nervously**

[@zacharygilmore1075]

The answer to the bonus riddle is 7 moves. 8, 5, 10, 7, 14, 28, 25.

[@andreasgtech]

I found 7 too, but it seems to me like it's too many moves :/ Perhaps there's a solution with fewer moves? Or is there a proof to state that 7 is the least number of moves?

[@szhzs6121]

6

[@yelena_]

andreasgtech It's 7 moves, it can be proven by constructing a tree that starts with 25 (or 28) as the root that branches into two by dividing the number by 2 or adding 3, until you get to 11

[@khushihooda7]

Zachary Gilmore I also got the same, but I think it's too many, I even constructed a tree but the answer I still got was 7

[@outsidestuff5283]

First ted ed riddle ive ever cracked

[@hajime486]

Same!!!!!!

[@marz4807]

Omg yay I was able to solve this one without help!

[@martinhoude3518]

Nailed it! The sequence of the original additions is really key.

[@cq.cumber_offishial]

Solution 1: pop the buttons back in. Solution 2: ask Agent Delta or whoever to hack the display to say "5 10 14"

[@MiMiBrokenbourgh]

2

[@amanah3421]

4:39 11-3=8 8-3=5 5x2=10 10x2=20 20x2=40 40-3=37 37-3=34 34-3=31 31-3=28 28-3=25 I did it

[@tcxd1164]

amanah tigetige The shortest amount of moves is 7. You can try reaching that if you want to.

[@theffects9545]

He didn’t say you had to do it you just had to figure out whats the minimum solution

[@miencraftlord7725]

Everybody is vibing and stuff but at 0:35 the enter button is on the space key

[@mobileminecrafter1385]

For the bonus riddle: 11-3=8, 8-3=5, 5x2=10, 10x2=20, 20-3=17, 17-3=14, 14x2=28, 28-3=25. This was easy

[@j23guntur]

for bonus riddle: 11 (-3) 8 (-3) 5 (x2) 10 (-3) 7 (x2) 14 (x2) 28 (-3) 25 *flies away

[@pauljk-123]

Got this one pretty easily

[@rickyuniverse4926]

Lelouch Yagami what do you want a prize...

[@pauljk-123]

Nah I'm just saying that this was one of their easier riddles

[@bananaforscale1283]

Right? There are even a few solutions!

[@TheRMeerkerk]

There are a lot of solutions I believe

[@CuongNguyen250690]

you are right. There are multiple solutions. However, the key points (x^2) are unique. And I think the video means that is unique.

[@khushbu2572]

love your video!!! It must have take more time to make than solving them!!!

[@messiah69420]

deepshikha khadka yep

[@tylerfox9482]

Since 25 isn't even, you'll have to get to it by subtracting 3, so you'll need to get to a number with a distance from 25 divisible by three. 28 is just 3 digits away from 25, and it's even which means you can get to it by doubling 14. The path looks like this. Subtract 3 twice to make 5. 11-3=8-3=5 Multiply by 2 twice to make 20. 5x2=10x2=20 Subtract 3 twice again to make 14. 20-3=17-3=14 Multiply by 2 to make 28. 14x2=28 Subtract 3 to make 25. 28-3=25 With this, you can make it in 8 moves.

[@teahu6473]

Your reasoning is completely sound but there is a way to get it done in 7 moves by making a change to one of your steps and then following through to 25.