# Can you solve the prisoner boxes riddle? – Yossi Elran

View full lesson: http://ed.ted.com/lessons/can-you-solve-the-prisoner-boxes-riddle-yossi-elran

Your favorite band is great at playing music…but not so great at being organized. They keep misplacing their instruments on tour, and it’s driving their manager mad. Can you solve the brain-numbing riddle their manager assigns them and make sure the band stays on their label? Yossi Elran shows how.

Lesson by Yossi Elran, animation by Artrake Studio.

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Fahad Hashmi is one of the known Software Engineer and blogger likes to blog about design resources. He is passionate about collecting the awe-inspiring design tools, to help designers.He blogs only for Designers & Photographers.

### 43 thoughts on “Can you solve the prisoner boxes riddle? – Yossi Elran”

• September 15, 2017 at 1:29 pm

Another way to solve it:

Step 1. Do everything wrong

Step 2. Just before the security comes, grab a few boxes

Step 3. Go out there, stuff the manager in the boxes, and wait..

• September 15, 2017 at 1:29 pm

I made one with at least 8 musicians will go to concert otherwords minimum 80% chance of musicians finding their instrument

• September 15, 2017 at 1:29 pm

Minute physics did this

• September 15, 2017 at 1:29 pm

wouldnt they have 6 guesses?
if they did the 5 guesses and they didn't find their instruments then you could say your instrument was on the next box in the loop and they would never notice if it was correct

• September 15, 2017 at 1:29 pm

but you can open only 5 boxes at a time what if ur instrument isnt on those?

• September 15, 2017 at 1:29 pm

Just leave the boxes open

• September 15, 2017 at 1:29 pm

If the first band made finds his the 2nd has a 5÷9 chance to find his and if the 2nd finds his he has a 5÷8 chance and so on

• September 15, 2017 at 1:29 pm

Or you can tell the manager to go stuff himself

• September 15, 2017 at 1:29 pm

but after someone open the right box and take his instrument, the box will be empty. That means that the next person may meet an empty box, and that will make it impossible to know which box continue the cicle.

• September 15, 2017 at 1:29 pm

one flaw: by the time the 2nd, 3rd, 4th etc. musicians tried to use the loop strategy, multiple boxes would have been empty. this is especially bad for the later (8th, 9th, 10th) musicians because only a few boxes have instruments in them, and odds are they wouldn't be able to follow a loop because they'd find most of the boxes to be empty and wouldn't be able to continue the loop. (example: 7th musician is the lead singer, they open the box with the microphone but its empty. this musician is forced to pick a completely random box, because theres no pattern to follow at this point– and theres no guarantee that the new box they pick would have an instrument, either..) so, about halfway through (starting around the 5th musician) most of the box-opening would be guesswork, ruining the point of the loop strategy. also, even though this problem is less likely to come up for the earlier (2nd, 3rd, etc) musicians, it's still a possibility, so the only band member who'd be certain to use the loop method without flaw would be the 1st musician. or am I just overspeculating?

• September 15, 2017 at 1:29 pm

Why do you assume that all different loops have the same probability? If the instruments have been placed randomly, then perhaps a loop that has more equivalent configurations would have a higher probability of occurring? You need to show that they all have the same chance of occurring.

• September 15, 2017 at 1:29 pm

this one is too difficult

• September 15, 2017 at 1:29 pm

If the rooms sound proof then tell them what's in what box

• September 15, 2017 at 1:29 pm

what if the 5th person opens a box and it is empty as four people who came
before him emptied four boxes, and he opens one of those empty boxes?

• September 15, 2017 at 1:29 pm

The written rule (1:40) does not contain that i cant go out with more than 1 person.

• September 15, 2017 at 1:29 pm

No way. This doesn't work. No drummer is that smart

• September 15, 2017 at 1:29 pm

This is the first riddle i solved

• September 15, 2017 at 1:29 pm

this only works if they don't take their instrument out of the box after looking

• September 15, 2017 at 1:29 pm

SOLUTION: If you don't find your instrument. When you get escorted back to the bus, flipping drive over the manager!

• September 15, 2017 at 1:29 pm

Wow this manager is bad he should be arrested

• September 15, 2017 at 1:29 pm

Am I the only one laughing at how bizarre the situation sounds?

• September 15, 2017 at 1:29 pm

imagine jake paul and team 10 take that test

• September 15, 2017 at 1:29 pm

I got it right yaaaaaaay

• September 15, 2017 at 1:29 pm

Then they fire their manager and sue him.

• September 15, 2017 at 1:29 pm

I had a feeling it would have something to do with the pictures but damn that's cool how that works

• September 15, 2017 at 1:29 pm

Dang I kinda got this one too…XD

• September 15, 2017 at 1:29 pm

NIce video, except for the graphics. Everything constantly shaking is annoying, to put it politely.

• September 15, 2017 at 1:29 pm

are the manager try to "saw"ing the band ?

• September 15, 2017 at 1:29 pm

Solution: guess randomly and sue the manager for kidnapping and breach of contract

• September 15, 2017 at 1:29 pm

@TED-ED, what's the guarantee that specific musical instrument would be in the display loop. For e.g., consider box labelled A,B,C. However, they contain instruments D,E,F. Similarly, box labelled D,E,F contain instruments A,B,C.

• September 15, 2017 at 1:29 pm

But what if u find an empty box where an instrument once was? Where do u go?

• September 15, 2017 at 1:29 pm

But if they're in a soundproof room, wouldn't they be able to talk while the manager is outside (not being able to hear their voices)?

• September 15, 2017 at 1:29 pm

Lol it will not work, how 'bout the last musicians to choose, they will be left with empty boxes that will take them no where.

• September 15, 2017 at 1:29 pm

But if you follow the answer than someone is going to find a empty box. If the drumer finds his drum in de box whit de guitar. The guitarist can't start a loop because the first box is empty.
Or didn't I understand it?

• September 15, 2017 at 1:29 pm

Strategy: Band picks the one Trump voting, gun toting redneck in the bunch to go first. They used to make fun of him but now they need him. He looks through the boxes, gets escorted to the tour bus. Calls police that his band members are kidnapped. Grabs 9mm and goes back into the room. Anyone who tries to stop him freeing his friends from felony kidnapping gets shot. Police arrive and arrest manager and security personnel. Band sues label for everything and makes \$\$\$\$\$.

• September 15, 2017 at 1:29 pm

The solution doesn't always work. I thought about that strategy and mapped out a few solutions. I didn't always find the box in five tries.

Ten boxes labeled A-J randomly filled with contents A-J. Look for G:

A-J
B-C x-3
C-F x-4
D-I x-6
E-A
F-D x-5
G-H x-1
H-B x-2
I-G bingo-7
J-E

It took seven boxes to find G.

• September 15, 2017 at 1:29 pm

I know an answer that will 70% work!
Step 1: Punch the guards
Step 2: Punch the manager
Step 3: Find the key
Step 4: Unlock the musicians
Step 5: Find the instruments
Step 6: Go on the tour bus
BOOM

• September 15, 2017 at 1:29 pm

Solution: quit working with this incredibly unprofessional record label, charge them with kidnapping, and since you've been stated to be highly talented you can find another label easily.