Can you solve the secret werewolf riddle? - Dan Finkel

3,865,828 views ・ 2018-11-08

TED-Ed


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譯者: Lilian Chiu 審譯者: Helen Chang
00:08
You’re on the trail of a werewolf
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你在追蹤一個狼人,
00:10
that’s been terrorizing your town.
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他一直在威脅你的小鎮。
00:12
After months of detective work,
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經過數個月的偵察,
00:14
you’ve narrowed your suspects to one of five people:
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你已經把嫌疑犯減少到五個人:
00:17
the mayor,
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市長、裁縫師、麵包師傅、
00:18
the tailor,
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00:19
the baker,
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00:20
the grocer,
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雜貨商,或是木匠。
00:21
or the carpenter.
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00:22
You’ve invited them to dinner with a simple plan:
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你邀請他們吃晚餐, 心中有個簡單的計畫:
00:25
you’ll slip a square of a rare werewolf antidote
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你要在每個人的晚餐中都偷偷
放入一片很稀有的 正方形狼人解藥。
00:28
into each of their dinners.
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00:30
Unfortunately, your pet goat just ate four of the squares,
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不幸的是,你的寵物山羊
吃掉了四片解藥,只剩下一片。
00:33
and you only have one left.
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00:36
Luckily, the remaining square is 50 grams,
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幸運的是,剩下的 那一片解藥有五十克,
00:39
and the minimum effective dose is 10 grams.
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最低有效劑量是十克。
00:42
If you can precisely divide the square into fifths
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如果你能精確地 把這片解藥分為五份,
00:45
you’ll have just enough antidote for everyone.
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你就能給每一個人足夠的解藥。
00:48
You’ll have to use a laser-cutting tool to cut up the square;
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你會需要用雷射 切割工具來切藥片;
00:52
every other means available to you isn’t precise enough.
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你能用的其他方式都不夠精確。
00:55
There are 8 points that can act as starting or ending points for each cut.
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有八個點可以當作每次切割的
起始點或是終點。
01:00
To use the device, you’ll have to input pairs of points
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若要使用這個裝置, 你需要輸入兩個點,
01:04
that tell the laser where to begin and end each cut,
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告訴雷射每次切割 從哪裡開始、哪裡結束,
01:07
and then the laser executes all the cuts simultaneously.
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接著雷射會同時執行所有的切割。
01:11
It’s okay to cut the square into as many pieces as you want,
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你想要把藥片切成幾塊都可以,
01:14
as long as you can group them into 10 gram portions.
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只要你能把它們湊成 十克的份量即可。
01:18
But you can’t fold the square or alter it otherwise,
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但你不能將藥片對折 或是用其他方式改變它,
01:21
and you only get one shot at using the laser cutter.
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你使用雷射切割器的 機會只有一次。
01:25
The full moon is rising,
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馬上就要滿月了,屆時就會有人
01:26
and in a moment someone will transform and tear you all apart
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變身狼人把你撕成碎片,
01:30
unless you can cure them first.
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除非你在這之前就把他們治癒。
01:32
How can you divide the antidote into perfect fifths,
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你要如何把解藥完美平分成五份,
01:35
cure the secret werewolf, and save everyone?
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治癒秘密狼人,拯救大家?
01:39
Pause the video now if you want to figure it out for yourself.
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如果你想要嘗試自己 解題,在這裡暫停。
01:43
Answer in 3
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答案即將公佈:三
01:44
Answer in 2
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答案即將公佈:二
01:45
Answer in 1
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答案即將公佈:一
01:47
When it comes to puzzles that involve cutting and rearranging,
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對於切割和重新排列的謎題,
01:51
it’s often helpful to actually take a piece of paper
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通常很有用的做法就是 真的拿一張紙出來,
01:54
and try cutting it up to see what you can get.
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把它切割開,試試看 你能得到什麼結果。
01:56
If we cut BF and DH we’d get fourths, but we need fifths.
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如果我們切割 BF 和 DH,
就會得到四份,但我們需要五份。
02:02
Maybe there’s a way to shave a bit off of a quarter to get exactly one fifth.
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也許有方法可以把四分之一再去掉 一點點,得到精確的五分之一。
02:06
Cutting BE looks good at first, but that last cut
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一開始,切割 BE 看起來不錯,
但最後一次切割會拿掉 四分之一的四分之一,
02:10
takes a off a quarter of a quarter,
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02:12
leaving us with a portion of 3/16: just smaller than a fifth,
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讓我們得到十六分之三,
比五分之一少一點,
02:17
and not enough to cure a werewolf.
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這劑量不夠治癒一個狼人。
02:19
What if we started with BE instead?
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如果我們改從 BE 開始呢?
02:22
That would also give us a quarter.
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那也會讓我們得到四分之一。
02:24
And is there a way to shave just a bit more off?
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有什麼方法可以 再多切掉一小部分嗎?
02:27
Both DG and CH look promising.
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DG 和 CH 看起來都很理想。
02:30
If we make one more cut, from A to F,
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如果我們再多切割 一次,從 A 到 F,
02:33
we may start to notice something.
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我們會開始注意到一些狀況。
02:36
With these four cuts—from B to E, D to G, F to A,
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若切割這四條線——
B 到 E、D 到 G、F 到 A、H 到 C ——
02:40
and H to C—we’ve got four triangles
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我們會得到四個三角形, 中間有一個正方形。
02:43
and a square in the middle.
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02:45
But the pieces that make each triangle can also be
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但組成每一個三角形的切片都能夠
02:48
rearranged to make a square identical to the middle one.
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被重新排列成一個正方形, 跟中間的一模一樣。
02:51
This means that we’ve split the antidote into perfect fifths!
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那就表示,我們把解藥 完美地分成五份了!
02:55
What’s interesting about this sort of problem
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關於這類問題,很有趣的就是
02:58
is that while it’s possible to solve it by starting from the geometry,
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雖然的確可能可以從幾何學開始,
03:01
it’s actually easier to start experimenting and see where that gets you.
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但用試驗的方式其實更容易些。
03:06
That wouldn’t be as viable if the square had, say, 24 cut points,
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如果方形藥片有比如二十四個點, 這招就不見得那麼可行了,
03:10
but with just 8 there are only so many reasonable options.
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但只有八個點時, 合理的選項就只有那麼多。
03:14
You secretly dose each of the townspeople
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當滿月出現時,你偷偷地
03:17
as the full moon emerges in the sky.
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在每個鎮民的食物中下藥。
03:19
And just as you do, a terrible transformation begins.
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你正在下藥時, 可怕的變身開始了。
03:23
Then, just as suddenly, it reverses.
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接著,突然,變身反轉了。
03:26
Your measurements were perfect,
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你測量的劑量恰到好處,
03:28
and the people and animals of the town can rest a little easier.
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這個小鎮的居民和動物 能夠更輕鬆地休息了。
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