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

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.

[baconlettucepotato]

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

[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*

[kirbomatic]

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

[surayasuraya]

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

[meinfisch]

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

[arhamhasan]

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

[Snacker]

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

[pammwhaff]

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

[Lolz]

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

Me: Imma head out

[atheistontheroad]

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

[darkeater]

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.

[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: 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.

[w]

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

[rayzhang]

1. Confirm you have green eyes.

2. Ask Mr. Schrödinger to leave.

[jamsekun]

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

[dailytofu]

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

[ayycarlito]

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

[memery]

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

[irinamacaroni]

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

[vivianitehawk]

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 🤷‍♂️