Can You Solve the Airplane Fuel Riddle?

Getty Images
Getty Images

Here's a fun riddle: Professor Fukanō plans to circumnavigate the world in his new airplane. But the plane's fuel tank doesn't hold enough for the trip—in fact, it holds only enough for half the trip. But with the help of two identical support planes (which can refuel him in mid-air) piloted by his assistants Fugori and Orokana, the professor thinks he can make it in one trip. But since all three planes have the same problem of limited fuel, how can they work together to achieve the professor's goal without anyone running out of fuel?

This TED-Ed riddle is very much like a Popular Mechanics riddle written in 2016. It's a tricky one, and it helps to have a piece of paper handy.

It's explained in the video below (along with a "pause now" bit so you can solve it yourself). If you're not a fan of video, here are the starting rules:

1. The professor's plane must make a single continuous trip around the world without landing or turning around.

2. Each plane can travel exactly 1 degree of longitude in 1 minute for every kiloliter of fuel. Each can hold a maximum of 180 kiloliters of fuel.

3. Any plane can refuel any of the others in mid-air by meeting at the same point and instantly transferring any amount of fuel.

4. Fugori and Orokana's planes can turn around instantaneously without burning fuel.

5. Only one airport is available for any of the planes to land, take off, or refuel.

6. All three planes must survive the experiment, and none may run of fuel in mid-air.

As the video explains, the airport mentioned in point #5 happens to be on the equator.

Here's the video:

For a bit more from TED-Ed on this riddle, check out this lesson page. If you want to read a solution to a very similar puzzle without watching the video above, try this Math is Fun puzzle page.

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Andrea Piacquadio / Pexels.com
Andrea Piacquadio / Pexels.com

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See What a Trailer for The Empire Strikes Back Might Look Like in 2020

Do or do not watch this trailer. There is no 'try.'
Do or do not watch this trailer. There is no 'try.'
Lucasfilm Ltd.

Special effects, cinematography trends, and acting styles may have changed over the last 40 years, but Star Wars: The Empire Strikes Back (1980) remains one of the most beloved film sequels—even among younger generations of Star Wars fans—to this day.

The trailer, on the other hand, seems pretty outdated, mainly due to the voiceover narration that expels lofty phrases like “an epic of romance, of heroes and villains,” and “a galactic odyssey against oppression.” To see what The Empire Strikes Back would look like with today’s trailer standards, YouTube user AD_edits created a new one, which relies on dialogue from the film itself to set the stage for the galactic odyssey against oppression.

As Nerdist points out, AD_edits’s trailer also manages to hint at important plot points without giving too much away, like mentioning that Luke must find a great Jedi master without revealing Yoda’s identity. The original, meanwhile, contains a couple outright spoilers—it shows, for example, Darth Vader sitting at the head of the table in Cloud City, waiting to ambush Han Solo and Princess Leia. Viewers might not have realized the significance when they saw the split-second clip in the trailer, but it would probably ruin the surprise when they watched the actual film.

Of course, there was always the possibility certain parts of the trailer could’ve ended up on the cutting room floor before the movie hit theaters, which has definitely happened before. The Cloud City scene made the final cut, but some storylines from earlier in the filmmaking process weren’t so lucky—in fact, most of the first draft for The Empire Strikes Back was completely scrapped. Find out about Darth Vader’s gargoyle-filled castle, Han Solo’s stepfather, and other axed ideas here.

[h/t Nerdist]