an ancient, abandoned alien space station filled with precursor technology.

一座古老、廢棄的外星人太空站，

But now, every species in the galaxy is in a mad dash to get there first

裡面滿是先驅級的科技。

and claim it for themselves.

但，現在，銀河系中的所有物種 都拼了命想要先趕到那裡，

And right away, you've got a problem.

搶先取得技術。

Your ship's faster-than-light jump drive consumes 1 unit of fuel

你馬上就遇到了一個問題。

for every parsec of distance it takes you,

你的太空船上具有 比光速還快的跳躍裝置，

and your ship holds only 15 units of fuel.

每當你行進 1 秒差距就需要 消耗 1 單位的燃料，

But the space station is 23 parsecs away,

而你的船只能裝 15 單位的燃料。

and there's only empty space between there and here.

但，太空站在 23 秒差距之外，

There's one thing that can help you, though:

從這裡到那裡之間， 都是空蕩蕩的空間。

dark matter fuel is stable in deep space.

不過，有一樣東西可以幫助你：

That means you can vent a cache of it from your fuel chamber,

在宇宙深處，暗物質 燃料是很穩定的。

and then come back to pick it up again later.

意思就是，你可以 從燃料室放出一個貯藏所，

Even though your ship holds only 15 units of fuel,

之後再回來將它取回。

you've been granted use of all 45 units in your current location.

雖然你的太空船只能 裝 15 單位的燃料，

With some strategic fuel caching along the way,

你已經得到許可，目前所在地 共有 45 單位，你都可以使用。

you might be able to make it all 23 parsecs.

在路上策略性地貯藏燃料，

So how can you reach the alien space station?

你就有可能行進 23 秒差距。

Answer in 3,

所以，你要如何抵達 外星人的太空站？

2,

[若想自行解題，可暫停播放]

1.

[答案即將公佈：3]

It's possible to solve this riddle using as few as two cache points,

[答案即將公佈：2]

and there are also valid solutions that use more.

[答案即將公佈：1]

No matter how you go about it though,

只要用兩個貯藏所的點 就可以解開這道題目，

the key is determining exactly where to cache fuel along your route.

另外也有使用更多貯藏點的 可行解決方案。

Let's work backwards from the alien space station.

不過，不論你要如何下手，

To reach 23 parsecs,

關鍵都在於要決定你這一路上 有哪些地方要貯藏燃料。

you'll have to leave the 8-parsec mark with a full tank of fuel.

咱們倒過來從外星人 太空站開始反推。

The 8-parsec point is too far from the start to use as a cache right away;

如果要行進 23 秒差距，

you could jump there, but wouldn't have enough fuel to return to the start,

你必須要在 8 秒差距的地方 留下滿滿一箱燃料。

let alone store any for later.

8 秒差距的地方，距離起始點太遠， 無法立即當作貯藏所；

So that means you'll need to find a cache somewhere between the start and 8.

你可以跳到那裡去，但就不會 有足夠的燃料返回起始點，

But where?

更不可能貯存任何 燃料供之後使用。

There's an interesting pattern that can help.

那就表示，你得要在起始點 和 8 之間找到一個貯藏所。

At the start you have exactly 3 tanks' worth of fuel.

但，要選哪裡？

At 8 parsecs you need exactly 1.

有一個有趣的模式， 可以派上用場。

Is there a point, which we can call point X, where you could have exactly 2?

在一開始，你有滿滿 3 箱的燃料。

That would be useful, because then you could refuel there exactly twice,

在 8 秒差距的地方， 你只需要剛好 1 箱。

making full use of your storage capacity without any waste.

有沒有一個 X 點，在這個 點上剛好有 2 箱燃料？

Wherever point X is,

知道這個會有幫助，因為 你可以在那裡補充燃料兩次，

you'll jump forward from it twice:

把貯藏容量用到極至， 完全不浪費。

once to deposit some fuel at the 8-parsec cache point, and a second time for good.

不論 X 點在哪裡，

So you'll jump the distance between X and 8-parsecs 3 times in all.

你會從 X 點向前跳兩次：

You'd have 2 tanks of fuel at point X, and need 1 left at the 8 parsec cache point,

第一次是要在 8 秒差距的 貯藏所存入一些燃料，

so you can spend one tank-- or 15 units-- going back and forth.

第二次則不用返回。

Since 15 units divided by 3 trips is 5,

所以，你總共要在 X 點 和 8 秒差距之間跳躍三次。

we can place these two cache points 5 parsecs apart.

在 X 點你會有 2 箱燃料，

Any farther, and you wouldn't have enough fuel to reach the alien space station.

在 8 秒差距的貯藏所 則需要留下 1 箱，

So it looks like the earliest we can place point X is at the 3-parsec mark.

因此，你只花費 1 箱—— 或說 15 單位——的燃料來往返。

Is it possible to transport 30 units of fuel there? Let's try.

15 單位平分給三趟 旅程，就是 5 單位，

You set out with a full tank of 15 units.

我們可以把這兩個貯藏所 之間的距離設定為 5 秒差距。

You jump 3 parsecs, drop 9 units off at the cache point,

再遠的話，你就沒有足夠燃料 可以到達外星人太空站了。

and then jump the 3 units home, arriving with an empty tank.

看起來，我們最早設下 X 點的 位置，是在 3 秒差距的地方。

Repeating this process gets you 18 units of fuel at the cache point,

有可能把 30 單位的燃料 運輸到那裡嗎？咱們試試。

and one more jump puts you at the 3-parsec cache with 30 total units of fuel.

你出發時，有滿滿 1 箱 15 單位的燃料。

So far so good!

你跳躍了 3 秒差距， 在貯藏所的地方置放下了 9 單位，

Next, you jump to the 8-parsec mark,

接著再花 3 單位跳躍，回到原點， 回去時剛好用光燃料。

drop off 5 units of fuel, and jump back to the 3-parsec mark.

把這個過程重覆執行， 在貯藏所就會有 18 單位，

You fill up your tank and jump forward again,

然後你再花 3 單位跳躍過去，

arriving with 10 units of fuel in your tank.

在 3 秒差距的地方 總共就有30 單位。

And now the end is in sight.

目前一切都很順利！

You beam the 5 units of fuel in from deep space to fill your tank to capacity,

接著，你要跳到 8 秒差距的地方，

and type in the coordinates of your final destination.

放下 5 單位，再返回 3 秒差距的地方。

A 15-parsec jump leaves you running on fumes,

你會把燃料箱裝滿， 再次向前跳躍，

but ready to dock with the precursor space station.

到達時你的燃料箱中 會有 10 單位。

Time to put this alien tech to work

現在，終點近在眼前。

and make life better for everyone in the galaxy.

你將來自太空深處的 5 單位燃料 存入你的燃料箱，裝到滿，