Stock Lateral Thinking Puzzle

Polygraph Operator: How would you say would be the easiest way to take a weapon away from a Grammaton Cleric?

Brandt: You ask him for it.

— Equilibrium

The trickier variant of the Stock Puzzle where the solution doesn't just require the application of logic and reasoning but the ability to think of things in another way. Frequently they are presented to appear like a difficult regular puzzle, but with a trick solution that is simple but not obvious.

Can sometimes be frustrating as it is often perfectly possible to construct a solution that explains all the presented facts in an unconnected way, but isn't the "right" answer that explains things by tying everything together.

These puzzles often may depend on semantics, cognitive theories, wordplay, and cultural codes and cues such as when (or when not to) take spoken words literally. As a result, such puzzles are not effectively translated into other languages. Nor are they universally considered fair measures of IQ or intelligence in general (except by 2000s-era job interviewers). In fiction, they can be life or death questions.

Such puzzles are also often subject to Rule Zero. In such cases, no other interpretation of the solution is acceptable than the specific one that is enforced, even in cases where alternate solutions are shown to make sense or when the enforced solution has been proven to be flawed or biased.

As there are entire websites dedicated to building collections of lateral thinking puzzles, please limit examples to puzzles that have been featured in the media (somewhere other than puzzle books).

Compare Outside-the-Box Tactic.

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St. Ives Puzzle

As I was going to St. Ives,
I met a man with seven wives.
Each of the wives had seven sacks,
Each of the sacks had seven cats,
Each of the cats had seven kits.
Kits, cats, sacks and wives,
How many were going to St. Ives?

Solution: One: you are, everyone else is going the other way. For those interested, there is 1 man, 7 wives, 49 sacks, 343 Cats and 2401 kits, making a total of 2801 going away from St. Ives (2800, not counting the man). Some versions add "Each of the kits have 7 mitts" which would be an extra 16807 mitts for a total of 19608. Depending on the wording, this can be something of a cheat, as it's never specified what direction the others were going, if any. There are several other possible objections about the wording, but those are left as an exercise for the reader.

• A variant asks instead, "How many T's are in all of that?", seemingly turning the numbers into a red herring. It is, but not in the way it appears. There are two T's in "all of that".
• Die Hard with a Vengeance: As part of Simon's game, Carver and McClane must solve the riddle and dial him back on 555-[The answer] before a bomb explodes. They get the answer right (555-0001) but are told they were too slow. However, there is no bomb because "I didn't say 'Simon Says'".
• Knights of the Old Republic: If you opened the mysterious box from Lurze, you get trapped inside the mind prison with its only other (sane) occupant. They challenge you to a battle of wits to see who has the right to escape to your body, and you exchange riddles until one of you gets stumped. After both parties succeed a few times each, your character eventually poses this riddle to the prisoner, and he panics, taking it as a standard math problem.
• Subverted and parodied in the July, 1983 issue of MAD, where it ends up not even being a riddle:
  As I was going to St. Ives,
  I met a man with seven wives.
  Of course, the seven wives weren't his,
  But in France, that's just how it is.
• Sesame Street: The girl calculates the total number of people as the song is sung the second time and reveals her answer after being told the trick.
  • And again with Kermit singing it as a song, with Grover frantically trying to keep track of the total.
• A John Finnemore's Souvenir Programme skit with the typical John Finnemore formula of a Sensible Person finding themselves in a stock storyline and deconstructing it. In this case, the final punchline is they're on a train to St. Ives.

3 + 5 = 4

How do you measure exactly 4 gallons using only a 3 and a 5 gallon jug?
Solution: Fill the 3, empty it into the 5 gallon, then refill the 3 gallon and fill the 5 gallon to the brim. You now have 1 gallon in the 3 gallon. Empty the 5 gallon jug, then put the remaining 1 gallon from the 3 gallon into the 5 gallon, refill the 3 gallon and empty into the 5 for exactly 4 gallons.

This has its own page as a Stock Puzzle, as it's somewhere between a lateral thinking puzzle and a regular logic puzzle. It's really about linear Diophantine equations, which are solvable by Euclid's algorithm using Bezout's lemma.

• Turns up in Die Hard with a Vengeance.
• One of the puzzles in Professor Layton.
• Knights of the Old Republic: In this example, the substance is gas pressure, but the method of solving it is exactly the same.
• The Runescape quest The Fremenik Trials uses this as part of a series of puzzles that Peer the Seer gives to you as part of his trial.
• Also used in the 2006 version of Safecracker.
• Myst IV: Revelation has a variant in Tomahna, where you have to reroute the Age's backup power from several buildings to the dam via this puzzle.
• There's a similar puzzle with different volumes in Zork Zero.
• The Cave features a variant in the Monk's story where 4 + 7 = 6.

Knights and Knaves

For examples of this puzzle, visit its page.

How Many Drivers?

You're driving a bus to London with 8 passengers. At the first stop half of them get off and twice that number get on. At the next stop 1/3 of them get off and 3/4 the number of remaining passengers get on. At the last stop before London 5 people get on. How many people are driving the bus when it reaches London?
Solution: One, buses only have 1 driver regardless of the number of passengers. One variant is asking how many stops the bus made. Other variants include asking the age, sex, or even eye color of the driver. The answer is whatever your age, sex, or eye color is as 'you' are driving the bus.

• The Touhou fan video "Cirno's Perfect Math Class" has a modified version of this puzzle (they wanted the number of people in total, rather than the number of people left on the bus); the answer Cirno gives is zero, because "there are no buses in Gensokyo". Given that Cirno is The Ditz, the absurdity of the answer makes sense in its own way.
• In Paper Mario: The Origami King, the Trial of Wisdom has Mario decide whether certain statements are true or false. One is "Twelve passengers are riding a bus. If five of them get off at their stops, seven people will remain on the bus." The answer is false: "There must be a driver on the bus as well, so eight people will remain...not seven."
• A variant occurs in the Finnish childrens' television series Hui Hai Hiisi, where Hiisi gives his dimwitted lackey Matti a riddle that begins, "You are the captain of a riverboat." He then continues with an absurdly long list of stops and passengers embarking and disembarking, finally ending with, "Who was the captain of the riverboat?" After some unsuccessful finger-counting, Matti manages to accidentally answer correctly by stammering, "I-I-I..."

The Doctor's Son

A man and his son are in a car accident and the both are injured. Both are taken to different hospitals (or the man dies). The doctor takes one look at him and says "I can't operate on this child, he's my son!" How is that possible?
Solution: Either the doctor is the boy's mother (the puzzle plays on people's tendency to assume certain gender roles unless explicitly told otherwise) or, in more recent tellings, the boy has two dads.

• Equally effective is the gender-flipped variation, where it is the boy's mother and a nurse objecting to the operation.
  • Used in a "Woman's Lib" episode of All in the Family, when Gloria asks the riddle of the rest of the family. Edith gets it right.
  • Used in an episode of The Cosby Show. In the setup, they refer to the doctor as "The old surgeon" and Cliff insists that the only reason he didn't get it is that no woman would allow herself to be referred to as "old."
  • A variant with a female circus performer was used in an Encyclopedia Brown story.
  • This riddle and several other listed here are lampshaded in The Office (US) Season 3 Episode 5 - "The Initiation". Dwight is attempting to teach Ryan - padawan style - the ways of the (sales) force, and is testing his intellect with a series of these hoary old riddles. Ryan knows them all and Dwight gets very frustrated until by the end, Dwight only has to say "A hunter..." and Ryan answers: It's a polar bear because you're at the North Pole.
  • Hank is asked this one in an episode of Corner Gas, and ends up suggesting that the doctor is a ghost. Brent didn't get it either and asks for clarification of why Hank's theory couldn't be true.
  • The children's toy robot 2-XL asked this riddle, asking the child whether the story was possible or not. After revealing the answer the robot broke down laughing at you.
  • Though it doesn't involve a doctor, the infamous "WHO WAS PHONE?!" joke Creepypasta is basically this.
  • Appears in a DVD-only scene from the "Road to the North Pole" episode of Family Guy, asked by an enchanted totem pole. Both Brian and Stewie immediately rule out the mother being the doctor, consider the above possibility of him having two fathers (comparing it to My Two Dads), and finally come to the conclusion that the doctor was a vampire. They're right.
  • In Tin Cup, Roy stumps his buddies with this question, until Molly, in a Walk-In Chime-In moment, answers the question, and mentions how the question is used to make people realize gender stereotypes.
• There's a variation that goes as follows: A man, his wife, and their son are in a car accident. They are all rushed to the hospital and the doctor says, "I can't operate on him, he's my son." Solution: The doctor is the man's father and the boy's grandfather.
  • Yet another variation has the police responding to a tip from someone claiming to have witnessed a crime. All they know is the perpetrator's whereabouts and that his name is John Smith. They arrive at an apartment and find a plumber, an electrician, a mechanic, and a roofer playing poker. None of them are wearing name tags or bearing any evidence of having committed a crime. Without communicating with each other, the police immediately arrest the mechanic. Why? He's the only man there. The other three are all women. This blue-collar variation is pretty effective, as women in these roles are less common than female doctors.
  • This riddle is sometimes used as a Secret Test of Character to test someone's implicit sexism or the like. Unfortunately, many people (women and feminists included) fail.

That's Impossible!

Various trick puzzles where it looks like there is a simple answer but it is in fact an invalid question:

• Who's buried in Grant's Tomb? Answer: No one is buried, but Grant and his wife are entombed there.
  • This riddle was popularized by Groucho Marx on his game show You Bet Your Life, is "Who is buried in Grant's Tomb?" Though the proper answer is "nobody" Groucho would usually accept just "Grant." Groucho would ask this question to contestants to ensure that they won something on his show. It can also be a snide trick question: When the responder answers "Ulysses Grant," he can be termed wrong for forgetting or not knowing that Julia Grant is there also.
  • This was averted in an episode of The Golden Girls, when it was the answer to Final Jeopardy in Dorothy Zbornak's dream sequence. Rose Nylund's response, "Who is Cary Grant?" is deemed to be the correct response by both host Alex Trebek and series creator Merv Griffin. (After all dream-Alex didn't specify that it was Ulysses Grant's tomb...)
  • "George Washington!"
  • Sometimes, people are tripped up because the answer of "Grant" seems too obvious. They assume that there must be a historical fact here they don't know, like maybe there was a mixup and the wrong body was placed in Grant's tomb. So they wind up guessing on something ridiculous and look silly.
  • In the April Fools' Day 2000 issue of Pyramid magazine, Kenneth Hite's Suppressed Transmission column is entitled "Mysteries of the Obvious — Explained!" Hite examines the question from conspiratorial, occultist, numerological, kabbalistic and literal angles, before coming to the conclusion that the answer might well be Ulysses S. Grant. "If so, it would answer a lot of questions. Or at least one."
  • "Hugh Grant?"
  • This does not work in languages that don't have separate terms for methods of interment. If you ever want to stop a pedant in their tracks, it doesn't work in English, either- "bury"'s primary definition is "to conceal" or "to protectively store away", as with a body in a tomb. The meaning of "to put in a hole and cover with dirt" is derived from its use to describe an interment, rather than the other way around.
• If a plane crashes exactly on a border, where are the survivors buried? Answer: The survivors are still alive and don't get buried anywhere.
  • Implied in the cold open of an episode of Batman: The Brave and the Bold. The Riddler has Batman and Booster Gold chained up on a mock game show set, and gives Batman an electric shock for each question Booster gets wrong. A montage of Booster's attempts includes "You don't bury survivors."
  • This one comes up in Corner Gas, the same episode as the Doctor one above, and again Hank screws it up. He first asks whether the plane is distributed more on one side than the other, and then when Karen emphasises the word "survivors", he answers. "Oh! One on each side."
  • Also comes up in the deleted final scene of Die Hard with a Vengeance. Simon gets it right instantly.
• If a rooster lays an egg on the exact peak of a barn, which side does it fall? Answer: Roosters don't lay eggs.
  • The Simpsons: In "Bart vs. Lisa vs. the Third Grade", Bart is dropped a grade and Lisa bumped up, leaving them both in the same class. This question stumps Lisa, but Bart gets it because he heard it the last time he was in that grade.
  • Again used in the Corner Gas episode, and Hank's answers include "The Alberta side," (referring to the plane crash example above). "The roof is flat," and "The egg is square!"
  • A variation of this was done in an ad in Australia in the late '90s/early '00s, for Smarties, if memory serves. "If a Daddy bull drinks 8 litres a day and a baby bull drinks 4 litres a day, how much does a Mummy bull drink?" The correct answer is that a 'Mummy bull' is an oxymoron - bulls are male cattle.
  • Another similar one is "What is the colour of an egg laid by a peacock?"
  • Additionally, the phrasing of this and other riddles means it would be perfectly valid to point out that saying the rooster doesn't lay eggs doesn't render the question invalid - if makes "a rooster lays an egg..." a premise and the rest of the question hypothetical, as in, "Roosters don't lay eggs, but if a rooster did, it could roll either way, and that's the question that was asked." See Many Questions Fallacy.
  • In legend, it would roll toward the dungheap, so that a toad or a serpent might hatch it. That's how you get the Basilisk and Cockatrice.
  • It's actually a Conviction by Counterfactual Clue. Anatomical differences between birds of different gender aren't as significant as between mammals, so some diseases or even the proper diet can, in fact, render a rooster capable of laying eggs. Cases were recorded and roosters were burned.
  • Also, in logic, a conditional statement (if..., then...) is always considered true if the first part is false. So if we take it that roosters cannot lay eggs, any answer for which way it rolls (indeed, any answer in general) is true. This is called a vacuous truth.
• How many animals of each kind did Moses bring on the Ark with him? Answer: Moses didn't have an Ark - at least, not one of the sort that animals could be put aboard, which was actually Noah's claim to fame.
  • Used by Samuel L. Jackson's character in Basic.
• Is the capital of Kentucky pronounced 'LOU-ee-vil' or 'LEW-iss-vil'? Answer: Neither. The capital of Kentucky is Frankfort. (And it's pronounced 'FRANK-furt', though people not from around there might not know that.)
  • Assuming that Louisville actually was was the capital of Kentucky, the answer would still be neither, since even the least nitpicky Kentuckian would tell you that Louisville is properly pronounced LOU-uh-vuhl.
  • And residents of the city in question would say only "LUHL-vuhul" is correct. Let's just say that the pronunciation is contentious.
  • Also commonly done with Florida and Miami, or with New Orleans, Louisiana. For an international city, Calcutta, India is used often. The capital of India is not pronounced "Cal-CUT-uh" or "CAL-ee-CUT" but rather New Delhi.

• How much dirt is there in a hole 2 meters by 2 meters by 2 meters? Answer: There isn't any dirt in a hole.
• Is it legal for a man to marry his widow's sister? Answer: No, because he's dead.
• Is it correct to say "the yolk of eggs is white" or "the yolk of eggs are white"? Answer: Neither, the yolk of eggs is yellow.
  • Mentioned in one Miss Marple story, where she compares it to the mystery, which is also based on a trick question.
  • In answer to the Red Herring question, when making a statement about the color of the yolk of eggs, under most prescriptive systems of English grammar one says "the yolk of eggs is." The subject is yolk, which is singular. Of course, many perfectly valid dialects do not necessarily preserve this distinction, and many others allow or require the verb to agree with "eggs" instead of "yolk".
  • "Yolk of eggs is yellow" is grammatically the more correct of the two choices as yolk is a substance, and substances in English use a rare construction called a "mass noun" which always uses the singular - like "milk". For most mass nouns, plurals would be interepreted as meaning different types of the substance, as in "the milks of different species of mammal". Now, "yolk" can also mean the inner structure of an egg, in which sense there are multiple such structures since there are multiple eggs - but in this case the grammatically correct statement would be "the yolks of eggs are yellow".
• If it takes six men six hours to dig six holes, how long does it take to dig half a hole? Answer: You can't dig half a hole. (Trivia game Mindtrap adds "A hole is a hole.")
• Similarly: If it took 10 men 20 days to build a wall, how long will it take 20 men to build that same wall? Answer: No time at all, that same wall is already built. (Note that this only works if you specifically say that wall is same as opposed to just any wall.)
• If you have a cube, each edge two inches long, how many total square inches are there among all eight faces? Answer: Hard to say, since cubes have six faces, not eight.
• A family of four wants toast for breakfast. The two children want one piece of toast each and the parents want two pieces of toast each. How many pieces of toast did they put into the toaster?/If roast goes into a roaster, what goes into a toaster? Answer: Toast does not go into a toaster. Bread does.

Tricks With Words

Often the trick is that the question being asked isn't actually the one you think due to tricky phrasing such as in a Riddle. Many of these are heavily dependent on the use-mention distinction, and hence work best when spoken aloud, as proper grammar necessitates the use of inverted commas which would give the game away.

• Floccinaucinihilipilification is a long word, how do you spell it? Answer: I, T spells "it".
  • In a similar vein: "Railroad crossing, look at the cars; can you spell that without any R's?" Obviously, the answer is "T-H-A-T".
• Think of words that end with the letters "gry". "Angry" is one, "hungry" is another. What is the third word in the English language?" The answer is "language" - there are, of course, no other actual English words with the suffix "-gry". ^note  Though, it could be "gry," a long-obsolete unit of measure, or Puggry, (one spelling for) a light scarf wrapped around a helmet, developed in India. ^{note 2} Strictly speaking, written versions of this riddle (like the above) need to be written slightly incorrectly to avoid giving away the answer, since "The English language" should be in quotation marks as well in order that the question would refer to the phrase rather than the language itself. The same goes for "it" and "that" above.
  • Hangry, a 21st century portmanteau of Hungry and Angry, renders this particular unsolvable puzzle defeated.
  • Curiously, this puzzle was invented by mistake. The original version merely asks for the third word containing "gry", which is "gryphon". Someone asked for a third word ending in "gry" by mistake, and since there isn't one, several trick answers (of which the "language" one is the most common) were invented to fill the vacuum.
  • Another variant of the riddle (which doesn't work in print) says there are three common words ending in "G or Y", which sounds really similar to "-gry". In this version, the riddle ends with "if you just listened to everything you heard me say, you just heard me say it. What is it?" The answer in this case is "say", which is a very common word ending in -y, and one which the speaker did indeed say multiple times.
  • There is also "anhungry", which was used by William Shakespeare in Coriolanus (Act I, scene i, line 209). It means "hungry".
  • Planescape: Torment had this very puzzle. Being based on Dungeons & Dragons rules, you had to solve it via your character's stats and not "your" own knowledge.
  • xkcd gives the appropriate response to this kind of trickery.
  • In the days of Usenet, the regulars of rec.puzzles coined the word "nugry" to mean a newbie who posted a puzzle which was already in the FAQ — especially the "gry" puzzle — to rec.puzzles.
• Raymond Smullyan's What is the Name of This Book? includes puzzles which take the reader to an island of Knights and Knaves. One puzzle reads: "This time you come across just one inhabitant lazily lying in the sun. You remember that his first name is either Edwin or Edward, but you cannot remember which. So you ask him his first name and he answers 'Edward.' What is his first name?" Answer: It's Edwin, because he was lying.
• If two's company, and three's a crowd, what are four and five? Answer: Nine.
• What is the difference between here and there? Answer: The letter "t".
• What is the beginning of eternity, and the end of time and space? Answer: The letter "e".
  • Alternatively, you can add on "The beginning of every end, and the end of every race."
  • Jackie Chan Adventures used almost this exact wording, only with "the end of every place."
  • In Harry Potter and the Goblet of Fire, the second part of the sphinx's riddle is "tell me what is the last thing to mend, the middle of middle and end of the end". Since the answer of the entire riddle is spider, the answer to the riddle is the letter "d", which is the last letter of the word mend, the middle letter of the word middle, and the last letter in the word end. Harry is stumped by that one, but guesses the first and third parts and figures out the answer to the riddle from those instead.
  • A longer riddle in Masquerade begins with "the beginning of eternity" and ends with "the end of time and space". The full answer is eclipse.
• What can be found in the middle of water? Typical answers would include "an island" or "Fish" ... The right answer is the letter "t". One could also correctly answer oxygen.
• I have sixty cups. Two drop to the ground and shatter. How many do I have left? Verbal only, as the answer is 4. It's six teacups. However, this is still forced because saying "six teacups" properly emphasizes the tea sound while "sixty cups" does not.
• You have a kerosene lamp, a wood stove, and a fireplace, and you have only one match to light them all with. What do you light first? Answer: The match, because it's what you're going to use to light the others. The way the question is phrased it can sound like 'Which one of the three items is the first one you light with the match?', but it's actually asking 'Out of everything present, which object is lit first?'
• What five-letter word does every college graduate spell/pronounce wrong? Answer: The word "wrong."
  • "The Princess of Pure Delight" from Lady in the Dark presents this as an Engagement Challenge.
  • This kind of falls apart when one remembers that not every college graduate speaks English.
  • The Batman uses this one in its Origins Episode for the Riddler, only with the eleven-letter word "incorrectly". His Asshole Victim gets this one right after some panic-fueled thinking, but that just triggers the next riddle and an even worse deathtrap. He gets the next one right too, but at that point Riddler has gotten bored of toying with him, calls an imaginary time limit, and springs the trap anyway.
• How many legs does a dog have if you call its tail a leg? Still four, as calling a tail a leg doesn't make it a leg.
• What occurs twice in a moment, once in a minute, but never in a thousand years? The letter M. Note that, like with the "words ending in -gry" riddle, this has to be written without quotation marks to avoid making it too easy.
• This riddle that was viral on Facebook, where those who got it wrong were forced to change their profile picture to a giraffe: It's 3:00 am, the doorbell rings and you wake up. Unexpectedly, it's your parents and they are there for breakfast. You have strawberry jam, honey, wine, bread and cheese. What is the first thing you open? The door. Like the match puzzle, it tricks people into thinking that the jam jar should be opened first because its phrasing sounds like "out of the food listed, which one should be opened first?"
  • A variant of this riddle has the food stored in the fridge and the one being asked asleep when the doorbell rings. Now what is the first thing they should open? Their eyes, because they would need to wake up first before opening the door for their parents, and then open the fridge to open the jam jar to make breakfast for them.
• How many birthdays does the average person have? Only one. They just celebrate the anniversary every year.

How is this situation possible?

• Two coins add up to 30 cents and one of them isn't a nickel. What are they? Solution: A quarter and a nickel. One of them isn't a nickel, but the other one is.
  • Or, you use a 20 cent and a 10 cent coin. Euro-cent.
  • British variant: 60 pence, of which one coin isn't a 10p. 50 + 10 Or 25, of which one isn't a 5. 20 + 5
  • Scrubs: Used by JD to trick the Janitor and Troy, who are thoroughly confused by the wordplay. Their solution involves scouring a book for coin collectors, finding and pointing out a coin that the book prices at 29 cents, and are enraged when JD explains the real answer. Their response at the end of the episode is to pose a riddle of their own: "Two guys destroyed your bike with a crowbar and a bat. One of 'em wasn't me." This happens TWICE.
  • An episode of The Cosby Show has a member of the family tell this riddle as part of a bet.
  • An episode of The Office (US) has Dwight tell this riddle to Ryan, but he isn't fooled and answers correctly. Dwight is rather annoyed by that.
• Two girls look exactly alike, they were born on the same day, to the same mother, within an hour of each other, but they are not twins. How is this possible? Answer: They are two out of a set of triplets.
  • Or quadruplets, or quintuplets, or...
• Jennifer is 20 years old in 1980, but 15 years old in 1985. How? Answer: Because she's living in the years Before the Common Era/Before Christ. (Though if that's the case, it's unlikely she would be named Jennifer.)
  • Alternatively, 1980 and 1985 are apartment numbers or street codes. She simply moved some time after she turned 15.
• A cowboy rides into town on Friday. He stays three days, then rides out of town on Friday. How? Answer: The horse's name was Friday.
• The Queen song "'39" presents one of these: A traveller sets out in the year of '39, travels for one year, and returns in the year of '39, to find that the woman greeting him, who he at first thought was his girlfriend, is in fact his girlfriend's daughter, born and raised since he left. Solution: He's a space traveller, whose voyage lasted one year of ship time, but 100 years of Earth time. The video on the DVD version of the album makes this clear.
• A man is condemned to be executed. He's given a choice between a room full of fire, a room full of expert assassins with guns, and a room full of lions who haven't eaten in three years. He picks the third and survives. How? the lions had all starved to death after three years with no food.

Which of these two weighs more?

• The original form of the question was "A pound of lead or a pound of feathers?" The question is designed to play on the listener's inherent association of lead being heavier than feathers. Standard Solution: They both weigh the same since they're both a pound.
  • The most common variant instead asks: "A pound of gold or a pound of feathers?" This version plays on the listener's inherent association of gold being heavier than feathers, and also screws with people who already know the answer to the original version of the question. Solution: The feathers are heavier. The gold weighs about 373.2 grams while the feathers weigh about 453.6 grams. ^ExplanationThere are two different units of weight both informally called "a pound", just like there are different units of currency each informally called "a dollar". (Imagine the question "which costs more, a dollar's worth of Canadian rum or a dollar's worth of Australian rum?".) For historical reasons, one version is used to measure precious metals and the other is used to measure everything else. This rarely comes up nowadays because people don't have to e.g. bring gold to the market and weigh it to buy stuff anymore. But you can still encounter it if you attempt to formally purchase gold by weight (including in places that use the metric system).^{Longer explanation}In historical Europe, different industries disagreed on how much a pound was. For example, the precious metals industry said a pound was equal to 24×20×12 or 5760 grains of wheat, the wool industry said a pound was equal to 7000 grains of wheat, and there were many other different pounds that didn't survive to the present day. (One big motivation for the metric system was not only to ease conversions, but also to prevent more situations where units would change depending on which industry you were talking to.) Eventually, almost all other industries converged around the wool pound, while the precious metals industry stuck to its pound (known as the troy pound). Fast-forward several centuries, and the wool pound is by far the more common of the two, while people don't often weigh gold anymore. You can still find troy pounds/ounces in one place internationally - in the United Nations currency standards, gold has its own listing (as a "non-national" currency) and its denomination is 1 troy ounce. (Look up the official currency code XAU and try converting it into EUR/GBP/USD/etc.) Incidentally, the puzzle's answer is reversed if you ask "an ounce of gold/feathers", because the precious metals industry decided there were 12 ounces per pound (to match feet and inches), while the wool industry decided there were 16 ounces per pound (so a pound could be easily divided in half four times). The ounce of gold is heavier than the ounce of feathers.
  • Alternatively, interpret "a pound of feathers/gold" as "how much feathers/gold you can buy with £1", in which case the answer would almost certainly be the feathers.
  • The "Engineer's/Lawyer's answer" to the "gold" variant: If the two don't weigh the same, the initial statement is dangerously unsafe. Using a single term to refer to two non-equivalent units would be a failure to document critical information. Replace feathers and gold with safe structural loads, and the trick question becomes grounds for serious criminal charges.
  • A standard way of playing it for laughs is answering "Drop them on your toes, and you'll find out."
  • A joke answer goes, "The feathers are heavier, because of the weight of what you did to those poor birds." (Although, birds can drop feathers naturally if you're patient enough...)
  • Which weighs more, a pound or an ounce? An ounce (snow leopard) is heavier than a pound (coin).
• Ali G had a quiz sketch which posed this question to the contestant. The contestant gets it straight away, but Ali has to have it explained to him by the quiz producers.
• In Pelle the Conqueror Pelle tries the gold-and-feathers question on his schoolteacher and gets a rap on the knuckles in response.
• Inside Man has the bank robber ask the question of which weighs more, "all the trains that pass through Grand Central Station in a year - or the trees cut down to print all U.S. currency in circulation?" The NYPD think it's the former once they figure out the U.S. currency part, but Frazier is smart enough to recall Dalton saying it was a trick question and the answer is always they both weigh the same, before deducing both answers. The answer to both is 0: U.S. currency is made of cotton; Grand Central Station is the name of the post office and the informal name of Grand Central Terminal. Humorously, after answering that the police then start debating among themselves whether the question is wrong anyway, as no trains pass through Grand Central because all of its tracks terminate there, unless you include the tracks of the subway stations.
• When Jerry rhetorically asks Danny this question in Nukees, Danny points out, after some caveats, that a pound of lead would displace less air, and therefore weigh more.
• Limmy's Show has a sketch where Limmy, in the guise of an edutainment programme narrator, asks the audience whether a kilogramme of steel is heavier than a kilogramme of feathers. Limmy's the only one to get the question wrong, and he seems to have a breakdown as everyone around him tries to explain "They're both a kilogramme."
• This is a good way to teach the concept of the mole in your chemistry class. While it is true they both weigh a pound, there will be more feathers in that pound than bricks. The mole is the base measuring unit to determine how much is in one atomic unit of an element.
• In Paper Mario: The Origami King, this is used as a true-or-false statement in the Trial of Wisdom: "One ton of iron is heavier than one ton of cotton." The answer is false: "One ton equals one ton. The density of the individual materials does not matter."

What kind of bear were they hunting?

• A group of hunters chases a bear 1 mile south, then 1 mile east, then 1 mile north. Now they're back where they started. What kind of bear were they hunting? A polar bear. That path is only geometrically possible at the poles. Incidentally, the hunt is only ecologically possible at the North Pole, since the South doesn't have any bears.
  • In The Office (US), this was one of the questions Dwight tried to confound the new guy with, but he has also read a lot of Mind Trap so he answers the each question nearly instantly.
  Dwight: A hunter-
  Ryan: It's a polar bear because you're at the North Pole.
  Dwight: DAMMIT!
  • A variant: you live in a house. All four walls face south. You look out the window and see a bear. What color is the bear?
  • This question pops up in a Dungeons & Dragons source book (2nd edition Complete Bard), but without the bear. Rather, a character asks in how many places this is possible, then smugly and condescendingly points out that your answer of "the north pole" is wrong, since he asked "how many" and the answer therefore is "one" (missing the point that, because of the south pole issue, the answer should be "infinity").
  • This question (without the bear - just asking where you started) used to be a part of interviews at SpaceX. Most engineers could figure out the North Pole answer easily, but there are actually infinitely many answers. You could start somewhere near the South pole such that going south would lead you to the latitude where going a mile east takes you around the South pole, then you go north back to where you started. Since you could also get around the pole twice if you started closer to it (or three times, etc.), there are infinitely many solutions.
• The Dream Park novel The California Voodoo Game uses this as the basis for a really tough logic puzzle. The measurements are the same, but the hunter runs down a bird instead of shooting a bear. Obviously (he's near the south pole), the solution is that he's a distance (the answer is a formula) that causes his "sideways" walking to carry him back to his original longitude.^note The starting point must be 1 + 1/(2πN) miles north of the South Pole, for positive integer N.
• A variant is used during the Riddler's introduction in The Batman, combining this with the "That's Impossible" type above: "A hunter walks one mile north of his camp and spots a bear. He tracks the bear one mile east, shoots the bear, then goes one mile south to arrive at his camp. What color is the bear?" Detective Yin, who has been working on the puzzles with Batman's remote help to this point, is about to enter White as the answer, when Batman shows up in person to stop her, as it's a trick question - this version of the riddle refers to the South Pole, where there are no bears, polar or otherwise. Turns out the riddles were just a distraction from the Riddler's real objective.^note  This variant didn't recognize that you could be some distance from the north pole, then travel east for exactly one mile (circling the north pole exactly N times), then return south to the original starting point.
• House: At the end of the episode "Failure to Communicate", House realizes the patient's illness causes him to say the word "bear" when he wants to say "polar". He then tells his subordinates this riddle to guide them towards this realization.
• The Mensa Puzzle Book has a puzzle that starts out like this, then says "I have no interest in the colour of the bear he shot, because there are no bears for miles", then says two other people, each some distance away, were doing the same thing, and asks how that is possible, pointing to the "somewhere near the South Pole" answer above. The answers page also says "The real mystery, of course, is what the devil they thought they were doing. For that there is no answer."
• A variant is used during the riddle contest in EP8 of Umineko: When They Cry. The bear-hunting is omitted, which changes the challenge to figuring out where you are. Your choices of answer are "a hot place", "a cold place", or "such a place doesn't exist".
• Used as a gag rather than a riddle in Good Omens, in which Shadwell is described as hating all Southerners (no one knows where he's from, as his accent is from all over the UK including Wales and Scotland) and by inference, lives at the North Pole.
• TED-ed has a variant on this one where the protagonist and their time-displaced self need to find two places where it's possible to head 1 mile South, 1 mile East, and then 1 mile North and end up where they started, in order to activate their time machines and set everything right. ^note The two places are the classic solution of the North Pole, and the other being 1 + 1/(2πn) miles north of the South Pole.