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.

Looking to Downsize? You Can Buy a 5-Room DIY Cabin on Amazon for Less Than $33,000

Five rooms of one's own.
Five rooms of one's own.
Allwood/Amazon

If you’ve already mastered DIY houses for birds and dogs, maybe it’s time you built one for yourself.

As Simplemost reports, there are a number of house kits that you can order on Amazon, and the Allwood Avalon Cabin Kit is one of the quaintest—and, at $32,990, most affordable—options. The 540-square-foot structure has enough space for a kitchen, a bathroom, a bedroom, and a sitting room—and there’s an additional 218-square-foot loft with the potential to be the coziest reading nook of all time.

You can opt for three larger rooms if you're willing to skip the kitchen and bathroom.Allwood/Amazon

The construction process might not be a great idea for someone who’s never picked up a hammer, but you don’t need an architectural degree to tackle it. Step-by-step instructions and all materials are included, so it’s a little like a high-level IKEA project. According to the Amazon listing, it takes two adults about a week to complete. Since the Nordic wood walls are reinforced with steel rods, the house can withstand winds up to 120 mph, and you can pay an extra $1000 to upgrade from double-glass windows and doors to triple-glass for added fortification.

Sadly, the cool ceiling lamp is not included.Allwood/Amazon

Though everything you need for the shell of the house comes in the kit, you will need to purchase whatever goes inside it: toilet, shower, sink, stove, insulation, and all other furnishings. You can also customize the blueprint to fit your own plans for the space; maybe, for example, you’re going to use the house as a small event venue, and you’d rather have two or three large, airy rooms and no kitchen or bedroom.

Intrigued? Find out more here.

[h/t Simplemost]

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These “Wonder Women” Bingo Cards Feature Amelia Earhart, Greta Thunberg, and 46 Other Inspiring Icons

You could even shout "Wonder Women!" instead of "Bingo!" if you want.
You could even shout "Wonder Women!" instead of "Bingo!" if you want.
Laurence King Publishing/Amazon

The original numbered version of bingo dates back to 16th-century Italy, but gamemakers have recently begun to realize that there’s no reason the classic game has to be quite so classic. Now, instead of numbers, you can find cards with pretty much any set of images or words you can think of (or you can simply make your own online).

This edition from Laurence King Publishing features illustrations of 48 incredible women who all, in some way, embody the name of the set: Wonder Women. There are sports champions like gymnast Simone Biles and tennis player Serena Williams alongside young living legends like climate change activist Greta Thunberg and education activist Malala Yousafzai. While you might recognize many of the names from history classes—Amelia Earhart and Rosa Parks, for example—or your own iTunes library (yes, Beyoncé is part of this game), others may be unfamiliar. Did you know about Russian cosmonaut Valentina Tereshkova, the first woman in space?

In other words, Wonder Women Bingo is a great way to celebrate your favorite trailblazers and get introduced to some new ones, too. And since the rules are simple—just pick a chip and see if your card has an image to match—it can also double as a learning opportunity for kids.

The illustrations were created by artist Laura Bernard.Laurence King Publishing/Amazon

The game is available for $35 on Amazon and $20 on Laurence King Publishing's website (though it's currently unavailable on Laurence King's site). And if bingo isn’t really your thing (or even if it is), there’s a Fantastic Women card game available for $13 on Amazon, where players try to top each other’s highest-scored cards using ones from their own hand.

While you’re waiting for your games to arrive, learn about 100 women who changed the world.

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