Can You Solve the Pirate Riddle?

iStock / VeraPetruk
iStock / VeraPetruk

In the video riddle below, we explore the distribution of pirates' booty. It gets complicated.

The scenario is this: Amaro is the captain of a pirate ship. His mateys, Bart, Charlotte, Daniel, and Eliza, are the other members of the crew. The group has come upon a bounty of 100 gold coins, and now must divide it up among the group according to "the pirate's code."

The code stipulates that Amaro, as captain, gets to suggest the first plan for distributing the coins among the five pirates. After that proposal, each pirate (including Amaro) votes "yarr" or nay on whether to accept the proposal. If the proposal results in either a tied vote (equal numbers "yarr"/nay) or a majority of "yarrs," it passes and the coins are immediately distributed. If it fails to meet this threshold, Amaro must walk the plank, making Bart the next captain. (Amaro walking the plank removes him from future votes, as well as eligibility for coin disbursals, on account of his death. Yuck.)

This process now repeats with Bart as captain, and the captain's hat will be passed on, in order, to Charlotte, Daniel, and finally Eliza. (If it gets all the way to Eliza without a passing proposal, she gets the booty.)

To make the situation more complex, there are rules governing how the pirates act. First, they each want to stay alive (that's their highest priority), but their next priority is maximizing their personal gold horde. Second, they distrust each other—there are no alliances and they cannot collaborate on a strategy. Third, they are bloodthirsty, and would love to see a fellow pirate walk the plank if they think it won't affect their own gold distribution. Fourth, each pirate has excellent logical deduction skills, and they're aware that everyone has the same skills. For the purposes of the puzzle, we can assume everyone is logical and obeys all the rules.

So we arrive at the key problem for Amaro: What distribution should he propose to ensure he lives and maximizes his own gold return? In order to figure this out, we have to walk through the chain of events and sort it out. Get your scratch paper ready!

The video below explains this puzzle (and its solution); here are the "rules" as stated at the 1:48 freeze-frame:

1. The captain makes a proposal for splitting up the 100 gold coins, which everyone votes on. A proposal that gets a tie or a majority of yarrs passes. A proposal with a majority of nays fails, and the captain has to walk the plank. The new captain then makes a proposal. The order of succession is Amaro, Bart, Charlotte, Daniel, and Eliza.

2. Each pirate's primary objective is to stay alive.

3. Each pirate's secondary objective is to maximize his or her gold.

4. Each pirate will vote to make the others walk the plank, all other results being equal. There are no abstentions.

5. Each pirate knows that the others share the same set of preferences.

6. Pirates cannot collaborate, make promises to each other, or form alliances; there is no communication outside the proposal and the votes, and no other trickery like murder or bribery. Even though they're pirates.

7. Each pirate is a perfect logician and all of them know this about each other.

Think on this a bit, and for the answer, have a look:

For more on the puzzle, check out this TED-Ed page. For a solution (and longer/more complex versions), read this PDF of an article by Ian Stewart.

Amazon's Best Black Friday Deals: Tech, Video Games, Kitchen Appliances, Clothing, and More

Amazon
Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Black Friday is finally here, and Amazon is offering great deals on kitchen appliances, tech, video games, and plenty more. We will keep updating this page as sales come in, but for now, here are the best Amazon Black Friday sales to check out.

Kitchen

Instant Pot/Amazon

- Instant Pot Duo Plus 9-in-115 Quart Electric Pressure Cooker; $90 (save $40)

- Keurig K-Cafe Special Edition; $190 (save $30)

- Ninja OS301 Foodi 10-in-1 Pressure Cooker and Air Fryer; $125 (save $75)

- Nespresso Vertuo Next Coffee and Espresso Machine by Breville; $120 (save $60)

- KitchenAid KSMSFTA Sifter with Scale Attachment; $95 (save $75)

- Keurig K-Mini Coffee Maker; $60 (save $20)

- Cuisinart Bread Maker; $80 (save $97)

- Anova Culinary Sous Vide Precision Cooker; $139 (save $60)

- Aicook Juicer Machine; $35 (save $15)

- JoyJolt Double Wall Insulated Espresso Mugs - Set of Two; $14 (save $10)

- Longzon Silicone Stretch Lids - Set of 14; $16 (save $11)

- HadinEEon Milk Frother; $37 (save $33)

Home Appliances

Roomba/Amazon

- iRobot Roomba 675 Robot Vacuum with Wi-Fi Connectivity; $179 (save $101)

- ASAKUKI 500ml Premium Essential Oil Diffuser; $22 (save $4)

- Facebook Portal Smart Video Calling 10 inch Touch Screen Display with Alexa; $129 (save $50)

- Bissell air320 Smart Air Purifier with HEPA and Carbon Filters; $280 (save $50)

- Oscillating Quiet Cooling Fan Tower; $59 (save $31)

- TaoTronics PTC 1500W Fast Quiet Heating Ceramic Tower; $55 (save $10)

- Vitamix 068051 FoodCycler 2 Liter Capacity; $300 (save $100)

- Ring Video Doorbell; $70 (save $30)

Video games

Sony

- Marvel's Spider-Man: Game of The Year Edition for PlayStation 4; $20 (save $20)

- The Legend of Zelda: Link's Awakening; $40 (save $20)

- Hyrule Warriors: Age of Calamity; $50 (save $10)

- Marvel's Avengers; $25 (save $33)

- The Last of Us Part II for PlayStation 4; $30 (save $30)

- LEGO Harry Potter: Collection; $15 (save $15)

- Ghost of Tsushima; $40 (save $20)

- BioShock: The Collection; $20 (save $30)

- The Sims 4; $24 (save $20)

- God of Warfor PlayStation 4; $10 (save $10)

- Days Gonefor PlayStation 4; $20 (save $6)

- Luigi's Mansion 3 for Nintendo Switch; $40 (save $20)

Computers and tablets

Microsoft/Amazon

- New Apple MacBook Pro 16 inches with 512 GB; $2149 (save $250)

- Microsoft Surface Laptop 3 with 13.5 inch Touch-Screen; $1200 (save $400)

- Lenovo ThinkPad T490 Laptop; $889 (save $111)

- Amazon Fire HD 10 Tablet (64GB); $120 (save $70)

- Amazon Fire HD 10 Kids Edition Tablet (32 GB); $130 (save $70)

- Apple iPad Mini (64 GB); $335 (save $64)

- Vankyo MatrixPad S2 Tablet; $120 (save $10)

Tech, gadgets, and TVs

Apple/Amazon

- Apple Watch Series 3 with GPS; $120 (save $79)

- Seneo Wireless Charger, 3 in 1 Wireless Charging Station; $16 (save $10)

- SAMSUNG 75-inch Class Crystal 4K Smart TV; $998 (save $200)

- Nixplay 2K Smart Digital Picture Frame 9.7 Inch Silver; $238 (save $92)

- All-New Amazon Echo Dot with Clock and Alexa (4th Gen); $39 (save $21)

- MACTREM LED Ring Light 6" with Tripod Stand; $16 (save $3)

- Amazon Fire TV Stick with Alexa Voice Remote; $28 (save $12)

- DR. J Professional HI-04 Mini Projector; $93 (save $37)

Headphones and speakers

Beats/Amazon

- Beats Solo3 Wireless On-Ear Headphones; $120 (Save $80)

- Apple AirPods Pro; $169 (save $50)

- Anker Soundcore Upgraded Bluetooth Speaker; $22 (save $8)

- Powerbeats Pro Wireless Earphones; $175 (save $75)

- JBL Boombox; $280 (save $120)

Movies and TV

HBO/Amazon

- Game of Thrones: The Complete Series; $115 (save $89)

- Jurassic World 5-Movie Set; $23 (save $37)

- Deadwood: The Complete Series; $42 (save $28)

- Back to the Future Trilogy; $15 (save $21)

Toys and Games

Amazon

- Awkward Family Photos Greatest Hits; $15 (save $10)

- Exploding Kittens Card Game; $10 (save $10)

- Cards Against Humanity: Hidden Gems Bundle; $14 (save $5)

- LOL Surprise OMG Remix Pop B.B. Fashion Doll; $29 (save $6)

- LEGO Ideas Ship in a Bottle 92177 Expert Building Kit; $56 (save $14)

Furniture

Casper/Amazon

- Casper Sleep Element Queen Mattress; $476 (save $119)

- ZINUS Alexis Deluxe Wood Platform Bed Frame; $135 (save $24)

- ROMOON Dresser Organizer with 5 Drawers; $59 (save $11) 

- AmazonBasics Room Darkening Blackout Window Curtains; $26 (save $5)

- Writing Desk by Caffoz; $119 (save $21)

- SPACE Seating Office Support Managers Chair; $112 (save $116)

- Rivet Globe Stick Table Lamp; $53 (save $17)

- Christopher Knight Home Merel Mid-Century Modern Club Chair; $188 (save $10)

- Walker Edison Furniture Industrial Rectangular Coffee Table; $121 (save $48)

Beauty

Haus/Amazon

- MySmile Teeth Whitening Kit with LED Light; $21 (save $12) 

- Cliganic USDA Organic Lip Balms Set of Six; $6 (save $4)

- HAUS LABORATORIES By Lady Gaga: LE RIOT LIP GLOSS; $7 (save $11)

- Native Deodorant for Men and Women Set of Three; $25 (save $11) 

- BAIMEI Rose Quartz Jade Roller & Gua Sha; $14 (save $3)

- Honest Beauty Clearing Night Serum with Pure Retinol and Salicylic Acid; $20 (save $8)

- WOW Apple Cider Vinegar Shampoo and Hair Conditioner Set; $30 (save $5) 

- La Roche-Posay Effaclar Purifying Foaming Gel Cleanser; $15 (save $5)

- wet n wild Bretman Rock Shadow Palette; $9 (save $6)

- EltaMD UV Daily Tinted Face Sunscreen Moisturizer with Hyaluronic Acid; $25 (save $6)

Clothes

Ganni/Amazon

- Ganni Women's Crispy Jacquard Dress; $200 (save $86) 

- The Drop Women's Maya Silky Slip Skirt; $36 (save $9)

- Steve Madden Women's Editor Boot; $80 (save $30)

- adidas Women's Roguera Cross Trainer; $40 (save $25)

- Line & Dot Women's Elizabeth Sweater; $74 (save $18)

- Levi's Men's Sherpa Trucker Jacket; $57 (save $41)

- Adidas Men's Essentials 3-Stripes Tapered Training Joggers Sweatpants; $28 (save $12)

- Timex Men's Weekender XL 43mm Watch; $32 (save $20)

- Ray-Ban Unisex-Adult Hexagonal Flat Lenses Sunglasses; $108 (save $46) 

- Reebok Men's Flashfilm Train Cross Trainer; $64 (save $16)

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Watch: In 1948, Idaho Officials Sent 76 Beavers Parachuting Into Idaho’s Wilderness

A young beaver with all four feet firmly on the ground.
A young beaver with all four feet firmly on the ground.
yrjö jyske, Flickr // CC BY 2.0

When people started building up the area around Idaho’s Payette Lake after World War II, its original residents began interfering with irrigation and agricultural endeavors. They weren’t exactly staging an organized protest—they were just beavers doing what beavers do.

Nevertheless, officials at the Idaho Department of Fish and Game decided their best bet was to find a new home for the long-toothed locals. The surrounding wilderness provided plenty of options, but transportation was another issue entirely. Traversing the undeveloped, mountainous terrain would require both trucks and pack animals, and experts knew from past relocation efforts that beavers weren’t fond of either.

“Beavers cannot stand the direct heat of the sun unless they are in water,” department employee Elmo W. Heter explained in a 1950 report [PDF]. “Sometimes they refuse to eat. Older individuals often become dangerously belligerent ... Horses and mules become spooky and quarrelsome when loaded with a struggling, malodorous pair of live beavers.”

To keep Payette Lake’s beavers healthy and happy during the journey, their human handlers would need to find another method of travel. As Boise State Public Radio reports, that’s when Heter suggested making use of their leftover WWII parachutes.

Two beavers would sit inside a wooden box attached to a parachute, which could be dropped from an airplane between 500 and 800 feet above their new home in the Chamberlain Basin. The cables that fastened the box to the parachute would keep it shut during the flight, but they’d slacken enough for the beavers to open the box upon landing. After testing the operation with weights, Heter and his colleagues enlisted an older beaver named Geronimo for a few live trials.

“Poor fellow!” Heter wrote. “You may be sure that ‘Geronimo’ had a priority reservation on the first ship into the hinterland, and that three young females went with him.”

Once Geronimo had certified the safety of the mission, the team began migrating the whole beaver population. During the fall of 1948, a total of 76 beavers touched down in their new territory. It wasn’t without tragedy, though; one beaver fell to his death after a cable broke on his box. Overall, however, the venture was deemed much safer (and less expensive) than any trip on foot would have been. And when department officials checked in on the beavers a year later, they had already started improving their ecosystem.

“Beavers had built dams, constructed houses, stored up food, and were well on their way to producing colonies,” Heter wrote. As Idaho Fish and Game’s Steve Liebenthal told Boise State Public Radio, the area is now part of “the largest protected roadless forest” in the continental U.S.

You can watch the Idaho Fish and Game Commission’s full 14-minute documentary about the process below.

[h/t Boise State Public Radio]