Can you solve the prisoner boxes riddle? - Yossi Elran

10,957,059 views ・ 2016-10-03

TED-Ed


Dvaput kliknite na engleske titlove ispod za reprodukciju videozapisa.

Prevoditelj: Tomas Kurbanović Recezent: Sanda L
00:06
Your favorite band is great at playing music,
0
6875
3478
Tvoj omiljeni bend je odličan u sviranju,
00:10
but not so great at being organized.
1
10353
3121
ali ne tako dobar kada se treba organizirati.
00:13
They keep misplacing their instruments on tour,
2
13474
2790
Stalno zameću svoje instrumente na turneji,
00:16
and it's driving their manager mad.
3
16264
2500
a to izluđuje njihovog menadžera.
00:18
On the day of the big concert,
4
18764
1810
Na dan velikog koncerta,
00:20
the band wakes up to find themselves tied up
5
20574
2310
članovi benda probude se zatočeni
00:22
in a windowless, soundproof practice room.
6
22884
3680
u zvučno izoliranoj sobi za probe bez prozora.
00:26
Their manager explains what's happening.
7
26564
2240
Njihov menadžer objasni im što se događa.
00:28
Outside, there are ten large boxes.
8
28804
3230
Vani je deset velikih kutija.
Svaka sadrži jedan od vaših instrumenata,
00:32
Each contains one of your instruments,
9
32034
2360
00:34
but don't be fooled by the pictures - they've been randomly placed.
10
34394
4820
ali ne dajte da vas slike zavaraju; postavljene su nasumično.
00:39
I'm going to let you out one at a time.
11
39214
3540
Puštat ću vas jednog po jednog.
00:42
While you're outside, you can look inside any five boxes
12
42754
3481
Dok ste vani, možete pogledati u bilo kojih pet kutija,
00:46
before security takes you back to the tour bus.
13
46235
3999
prije nego vas zaštitari vrate u autobus.
00:50
You can't touch the instruments
14
50234
1669
Ne smijete dirati instrumente
00:51
or in any way communicate what you find to the others.
15
51903
3901
ili na neki način drugima pokušati reći što ste našli.
00:55
No marking the boxes, shouting, nothing.
16
55804
3770
Nema označavanja kutija, vikanja, ničega.
00:59
If each one of you can find your own instrument,
17
59574
2571
Ako svatko od vas uspije naći svoj instrument,
01:02
then you can play tonight.
18
62145
1860
večeras možete svirati.
01:04
Otherwise, the label is dropping you.
19
64005
2999
U suprotnom, diskografska kuća raskida ugovor s vama.
01:07
You have three minutes to think about it before we start.
20
67004
3790
Imate tri minute za razmišljanje prije početka.
01:10
The band is in despair.
21
70794
1540
Bend je u očaju.
01:12
After all, each musician only has a 50% chance of finding their instrument
22
72334
4520
Svaki glazbenik ima samo 50% šanse za pronalaženje svog instrumenta,
01:16
by picking five random boxes.
23
76854
2480
bude li birao pet nasumičnih kutija.
01:19
And the chances that all ten will succeed are even lower -
24
79334
3316
Šanse da svi uspiju čak su i manje;
01:22
just 1 in 1024.
25
82650
3124
samo 1 : 1024.
01:25
But suddenly, the drummer comes up with a valid strategy
26
85774
2690
Iznenada, bubnjar je iznio razumnu strategiju
01:28
that has a better than 35% chance of working.
27
88464
4580
koja ima više od 35% šanse za uspjeh.
Možeš li shvatiti što je predložio?
01:33
Can you figure out what it was?
28
93044
2700
01:35
Pause the video on the next screen if you want to figure it out for yourself!
29
95744
8021
Pauziraj video na idućem zaslonu ako želiš sam riješiti zagonetku.
01:43
Answer in: 3
30
103765
1449
Odgovor za: 3
01:45
Answer in: 2
31
105214
1001
Odgovor za: 2
01:46
Answer in: 1
32
106215
1430
Odgovor za: 1
01:47
Here's what the drummer said:
33
107645
1640
Bubnjar je rekao sljedeće:
01:49
Everyone first open the box with the picture of your instrument.
34
109285
3771
Svatko neka prvo otvori kutiju sa slikom svojeg instrumenta.
01:53
If your instrument is inside, you're done.
35
113056
2319
Ako je unutra tvoj instrument, gotov si.
01:55
Otherwise, look at whatever's in there,
36
115375
2180
U suprotnom, pogledaj što je u kutiji
01:57
and then open the box with that picture on it.
37
117555
2880
i zatim otvori kutiju koja ima sliku tog instrumenta.
02:00
Keep going that way until you find your instrument.
38
120435
3070
Nastavi dok ne nađeš svoj instrument.
02:03
The bandmates are skeptical,
39
123505
1650
Članovi benda su skeptični,
02:05
but amazingly enough, they all find what they need.
40
125155
3070
no, začuđujuće, svi nađu što trebaju.
02:08
And a few hours later, they're playing to thousands of adoring fans.
41
128225
3871
Nekoliko sati kasnije, sviraju za tisuće svojih obožavatelja.
02:12
So why did the drummer's strategy work?
42
132096
2559
Zašto je bubnjarova strategija djelovala?
02:14
Each musician follows a linked sequence
43
134655
2630
Svaki glazbenik prati povezani niz
02:17
that starts with the box whose outside matches their instrument
44
137285
3660
koji počinje kutijom čija slika odgovara njihovom instrumentu
02:20
and ends with the box actually containing it.
45
140945
4060
i završava kutijom koja ga sadrži.
Opazi da bi se vratili na početak kada bi nastavili,
02:25
Note that if they kept going, that would lead them back to the start,
46
145005
3500
02:28
so this is a loop.
47
148505
1601
dakle, ovo je petlja.
02:30
For example, if the boxes are arranged like so,
48
150106
2819
Na primjer, da su kutije ovako poslagane,
02:32
the singer would open the first box to find the drums,
49
152925
3109
pjevačica bi otvorila prvu kutiju i našla bubnjeve,
02:36
go to the eighth box to find the bass,
50
156034
2231
otišla do osme kutije i našla bas gitaru
02:38
and find her microphone in the third box,
51
158265
2800
i našla mikrofon u trećoj kutiji,
02:41
which would point back to the first.
52
161065
2821
koja bi je vodila natrag do prve.
02:43
This works much better than random guessing
53
163886
2589
Ovo djeluje puno bolje od nasumičnog pogađanja,
02:46
because by starting with the box with the picture of their instrument,
54
166475
3349
jer ako započne kutijom sa slikom svojeg instrumenta,
02:49
each musician restricts their search to the loop that contains their instrument,
55
169824
4611
svaki glazbenik ograničava potragu na petlju koja sadrži njihov instrument
02:54
and there are decent odds, about 35%,
56
174435
3401
i postoji pristojna mogućnost, oko 35%,
02:57
that all of the loops will be of length five or less.
57
177836
4441
da će sve petlje biti duge pet ili manje koraka.
03:02
How do we calculate those odds?
58
182277
1648
Kako smo izračunali tu mogućnost?
03:03
For the sake of simplicity, we'll demonstrate with a simplified case,
59
183925
3802
U svrhu jednostavnosti, demonstrirat ćemo na pojednostavljenom slučaju;
03:07
four instruments and no more than two guesses allowed for each musician.
60
187727
5759
četiri instrumenta i ne više od dva pokušaja po glazbeniku.
03:13
Let's start by finding the odds of failure,
61
193486
2841
Počnimo pronalaženjem mogućnosti neuspjeha,
03:16
the chance that someone will need to open three or four boxes
62
196327
3350
slučajem da će netko morati otvoriti tri ili četiri kutije,
03:19
before they find their instrument.
63
199677
2048
prije nego pronađe svoj instrument.
03:21
There are six distinct four-box loops.
64
201725
2591
Postoji šest jedinstvenih petlji s četiri kutije.
03:24
One fun way to count them is to make a square,
65
204316
3141
Jedan zabavan način da ih izbrojiš jest da napraviš kvadrat.
03:27
put an instrument at each corner,
66
207457
2169
Stavi po jedan instrument u svaki kut
03:29
and draw the diagonals.
67
209626
2161
i povuci dijagonale.
03:31
See how many unique loops you can find,
68
211787
2830
Vidi koliko jedinstvenih petlji možeš naći,
03:34
and keep in mind that these two are considered the same,
69
214617
3490
ali imaj na umu da se ove dvije smatraju jednakima,
03:38
they just start at different points.
70
218107
2030
samo kreću iz različite točke.
03:40
These two, however, are different.
71
220137
2261
Međutim, ove su dvije različite.
03:42
We can visualize the eight distinct three-box loops using triangles.
72
222398
4700
Možemo si predočiti osam različitih petlji s tri kutije koristeći trokute.
03:47
You'll find four possible triangles
73
227098
2350
Naći ćeš četiri moguća trokuta,
03:49
depending on which instrument you leave out,
74
229448
2569
ovisno o instrumentu kojeg izostaviš,
03:52
and two distinct paths on each.
75
232017
2931
i dva različita puta na svakom.
03:54
So of the 24 possible combinations of boxes,
76
234948
3381
Dakle, od 24 mogućih kombinacija kutija,
03:58
there are 14 that lead to faliure,
77
238329
2469
14 ih vodi k neuspjehu,
04:00
and ten that result in success.
78
240798
2600
a 10 rezultira uspjehom.
04:03
That computational strategy works for any even number of musicians,
79
243398
5070
Ta računska strategija vrijedi za sve parne brojeve glazbenika,
04:08
but if you want a shortcut,
80
248468
1380
no, ako želiš kraticu,
04:09
it generalizes to a handy equation.
81
249848
3960
može se svesti na korisnu jednadžbu.
04:13
Plug in ten musicians, and we get odds of about 35%.
82
253808
4299
Uključi deset glazbenika i dobit ćemo šanse od oko 35%.
04:18
What if there were 1,000 musicians?
83
258107
2321
Što kada bismo imali tisuću glazbenika?
04:20
1,000,000?
84
260428
1370
Milijun?
04:21
As n increases, the odds approach about 30%.
85
261798
4400
Kako se n povećava, šanse se približavaju 30-ak posto.
04:26
Not a guarantee, but with a bit of musician's luck, it's far from hopeless.
86
266198
6030
Nije garancija za uspjeh, no uz malo sreće, stvar je daleko od beznadne.
04:32
Hi everybody, if you liked this riddle, try solving these two.
87
272228
3689
Ako vam se svidjela ova zagonetka, pokušajte riješiti ove dvije.
O ovoj web stranici

Ova stranica će vas upoznati s YouTube videozapisima koji su korisni za učenje engleskog jezika. Vidjet ćete lekcije engleskog koje vode vrhunski profesori iz cijelog svijeta. Dvaput kliknite na engleske titlove prikazane na svakoj video stranici da biste reproducirali video s tog mjesta. Titlovi se pomiču sinkronizirano s reprodukcijom videozapisa. Ako imate bilo kakvih komentara ili zahtjeva, obratite nam se putem ovog obrasca za kontakt.

https://forms.gle/WvT1wiN1qDtmnspy7