# See If You Can Solve This Tricky Coin-Flipping Riddle

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Make sure your head is in working order before trying to solve this riddle from TED-Ed, because it's a stumper.

Here's the scenario: You're an explorer who's just stumbled upon a trove of valuable coins in a remote dungeon. Each coin has a gold side and a silver side, each with an identical scorpion seal. The wizard who guards the coins agrees to let you have them, but he won't let you leave the room unless you separate the hoard into two piles with an equal number of coins with the silver side facing up in each. You've just counted the total number of silver-side-up coins—20—when the lights go out. In the dark, you have no way of knowing which half of a coin is silver and which half is gold. How do you divide the pile without looking at it?

As TED-Ed explains, the task is fairly easy to complete, no psychic powers required. All you need to do is remove any 20 coins from the pile at random and flip them over. No matter what combination of coins you choose, you will suddenly have a number of silver-side-up coins that's equal to whatever is left in the pile. If every coin you pulled was originally gold-side-up, flipping them would give you 20 more silver-side-up coins. If you chose 13 gold-side-up coins and seven of the silver-side coins, you'd be left with 13 silver coins in the first pile and 13 silver ones in your new stack after flipping it over.

The solution is simple, but the algebra behind it may take a little more effort to comprehend. For the full explanation and a bonus riddle, check out the video from TED-Ed below.

[h/t TED-Ed]

# 8 Surprising Uses for Potatoes

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Potatoes are one of the world’s most common, and most beloved, vegetables—and they can be used for much more than just sustenance. In honor of National Potato Day, here are a few other ways to use a potato.

#### 1. WEAR THEM

Potatoes come from a nightshade plant called Solanum tuberosum, which blooms with white, pink, red, blue, or purple flowers. In the late 1700s, in an effort to inspire their starving subjects to plant the newly introduced vegetable—which the Spanish had brought to Europe from the New World—Marie Antoinette wore potato flowers in her hair, and her husband King Louis XVI wore them in his buttonholes. This inspired potato flowers to be a favorite of the French nobility for a time, but the ploy didn't work: The lower classes spurned the upper class's efforts to get them to farm the crop.

#### 2. MAKE ELECTRICITY

If you’re in a lurch, or perhaps a doomsday prepper, start stocking up on potatoes now. With just a few household items—wires, some copper, and a zinc-coated nail—and one of the tubers, you can power a clock, a light bulb, and many other small electronics.

#### 3. GARDEN IN SPACE

In 1995, the potato became the first vegetable grown on the space shuttle. Raymond Bula of the University of Wisconsin spearheaded a project in which five Norland variety potato leaves were propagated in space. Bula’s research group monitored this project from Wisconsin, staying in constant contact with NASA, who stayed in contact with the crew on the space shuttle. When the shuttle arrived home, everyone was pleased to find that the potato plants not only survived the ordeal, but actually grew potatoes.

#### 4. GROW ROSES

Gardeners can insert rose cuttings into a potato, and then plant the entire potato as if it were a seed or bulb. The nutrient-rich potato helps provide moisture and sustenance to the growing plant, giving the cutting a better chance to survive.

#### 5. MAKE PLASTIC

Bio-plastics, as they’re called, can be made from corn, wheat, and—you guessed it—potatoes. The concentration of starches and cellulose in a potato can be used to make plastic, and the plastic made out of potatoes can be burned and composted with much less impact on the environment.

#### 6. MEASURE TIME

Peru’s Incas used the potato for all sorts of things at the height of their civilization. Known for creative, forward-thinking agricultural practices, the Incas also studied time—and started using the time it takes to cook a potato to measure time.

#### 7. REMOVE RUST

Have a knife with some rust spots? If you insert the knife into the potato and let it sit for awhile, you'll go a long way in removing the rust. Potatoes naturally contain oxalic acid, which is used in many household cleaning products (in much greater quantities, of course). Oxalic acid also dissolves rust. To attack larger rusted surfaces with a potato, cut it in half, sprinkle baking powder on it or dip it in dish soap, and get to scrubbing.

#### 8. MAIL THEM

Thanks to Mail A Spud, for only \$9.99 everyone’s dream of mailing a potato to their closest friends and family can be a reality. The site advertises that it can send potatoes anywhere in the U.S., and that your choice of mailed gift will be sure to delight recipients. And, if not delight, at least confuse ... in a good way.

Additional Sources: Potato: A History of the Propitious Esculent

# Get Paid to Write Dirty Jokes for Cards Against Humanity

If you've exhausted every possible joke combination in Cards Against Humanity, the makers of the game have a new outlet for your wit. Apply to be a contributing writer and you could get paid to write the gross, bizarre, and occasionally offensive cards that go into new editions of the game.

For the uninitiated, here's how Cards Against Humanity works: A player draws a black card, which has a sentence with a section missing from it, and puts it down for the group to see. The rest of the players then put down white cards with words or phrases that could potentially fill in the blank. The player who comes up with the best joke wins the round.

In order for the jokes to be funny, the cards themselves need to be well written. That's where the contributing writers come in. As the job posting explains, the new writers will make \$40 an hour "writing poop jokes as needed." The position is remote and part-time.

To see if you're a good fit for the gig, Cards Against Humanity is asking that you submit ideas for 15 white cards and five black cards that best exhibit your humor and writing skills. They've even included a handy primer on "how to write cards that don't blow" for applicants who are unsure of where to start. "A good black card allows players to subvert an expected tone or logic," the guidelines explain, while white cards should have "distinct voice, perspective, or syntax." The page also includes general guidelines on structure and the Cards Against Humanity style.

To apply, submit your ideas through the website before August 31. And if you're looking for some offbeat inspiration, this 19th-century version of the game should kickstart your creativity.

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