B2 中上級 204 タグ追加 保存
動画の字幕をクリックしてすぐ単語の意味を調べられます!
単語帳読み込み中…
字幕の修正報告
One of the kingdom's most prosperous merchants
has been exposed for his corrupt dealings.
Nearly all of his riches
are invested in a collection
of 30 exquisite Burmese rubies,
and the crowd in the square
is clamoring for their confiscation
to reimburse his victims.
But the scoundrel and his allies at court
have made a convincing case
that at least some of his wealth
was obtained legitimately,
and through good service to the crown.
The king ponders for a minute
and announces his judgment.
Because there's no way to know
which portion of the rubies were bought with ill-gotten wealth,
the fine will be determined through a game of wits between the merchant
and the king's most clever advisor – you.
You're both told the rules in advance.
The merchant will be allowed to discreetly divide his rubies
among three boxes, which will then be placed in front of you.
You will be given three cards,
and must write a number between 1 and 30 on each,
before putting a card in front of each of the boxes.
The boxes will then all be opened.
For each box, you will receive exactly
as many rubies as the number written on the corresponding card,
if the box has that many.
But if your number is greater than the number of rubies actually there,
the scoundrel gets to keep the entire box.
The king puts just two constraints on how the scoundrel distributes his rubies.
Each box must contain at least two rubies
and one of the boxes must contain exactly six more rubies than another—
but you won't know which boxes those are.
After a few minutes of deliberation,
the merchant hides the gems, and the boxes are brought in front of you.
Which numbers should you choose
in order to guarantee the largest possible fine for the scoundrel
and the greatest compensation for his victims?
Pause the video now if you want to figure it out for yourself.
Answer in 3
Answer in 2
Answer in 1
You don't want to overshoot by being too greedy.
But there is a way you can guarantee
to get more than half of the scoundrel's stash.
The situation resembles an adversarial game like chess –
only here you can't see the opponent's position.
To figure out the minimum number of rubies you're guaranteed to win,
you need to look for the worst case scenario,
as if the merchant already knew your move
and could arrange the rubies to minimize your winnings.
Because you have no way of knowing which boxes will have more or fewer rubies,
you should pick the same number for each.
Suppose you write three 9's.
The scoundrel might have allocated the rubies as 8, 14 and 8.
In that case, you'd receive 9 from the middle box and no others.
On the other hand, you can be sure that at least two boxes
have a minimum of 8 rubies.
Here's why.
We'll start by assuming the opposite,
that two boxes have 7 or fewer.
Those could not be the two that differ by 6,
because every box must have at least 2 rubies.
In that case, the third box would have at most 13 rubies—that's 7 plus 6.
Add up all three of those boxes,
and the most that could equal is 27.
Since that's less than 30,
this scenario isn't possible.
You now know, by what's called a proof by contradiction,
that two of the boxes have 8 or more rubies.
If you ask for 8 from all three boxes
you'll receive at least 16—
and that's the best you can guarantee,
as you can see by thinking again about the 8, 14, 8 scenario.
You've recovered more than half the scoundrel's fortune
as restitution for the public.
And though he's managed to hold on to some of his rubies,
his fortune has definitely lost some of its shine.
コツ:単語をクリックしてすぐ意味を調べられます!

読み込み中…

【TED】頭を絞ってルビーを受け取れよう!ーデニス・シャシャ (Can you solve the stolen rubies riddle? - Dennis Shasha)

204 タグ追加 保存
ally.chang 2020 年 2 月 5 日 に公開
お勧め動画
  1. 1. クリック一つで単語を検索

    右側のスプリクトの単語をクリックするだけで即座に意味が検索できます。

  2. 2. リピート機能

    クリックするだけで同じフレーズを何回もリピート可能!

  3. 3. ショートカット

    キーボードショートカットを使うことによって勉強の効率を上げることが出来ます。

  4. 4. 字幕の表示/非表示

    日・英のボタンをクリックすることで自由に字幕のオンオフを切り替えられます。

  5. 5. 動画をブログ等でシェア

    コードを貼り付けてVoiceTubeの動画再生プレーヤーをブログ等でシェアすることが出来ます!

  6. 6. 全画面再生

    左側の矢印をクリックすることで全画面で再生できるようになります。

  1. クイズ付き動画

    リスニングクイズに挑戦!

  1. クリックしてメモを表示

  1. UrbanDictionary 俚語字典整合查詢。一般字典查詢不到你滿意的解譯,不妨使用「俚語字典」,或許會讓你有滿意的答案喔