Logic puzzles: making deductions and speculating

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90 min
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1

Think about these questions before watching. Share your ideas with a partner.

  1. Some people are drawn to intricate brain teasers and logic puzzles, while others find them tedious. Which camp do you fall into, and what do you think this reveals about your preferred way of thinking?
  2. Describe your typical approach when faced with a complex problem that requires logical deduction. Do you meticulously map things out, rely on a flash of intuition, or use another method entirely?
  3. Beyond mere entertainment, what do you see as the real-world value of honing your deductive reasoning skills? In what professions or everyday scenarios is this type of sharp, analytical thinking indispensable?
2

Watch the video carefully. Pay attention to the main ideas and key details.

Video script89 segments · click a timestamp to jump

Before he turned physics upside down,

a young Albert Einstein supposedly showed off his genius

by devising a complex riddle involving this list of clues.

Can you resist tackling a brain teaser

written by one of the smartest people in history?

Let's give it a shot.

The world's rarest fish has been stolen from the city aquarium.

The police have followed the scent to a street with five identical looking houses.

But they can't search all the houses at once,

and if they pick the wrong one, the thief will know they're on his trail.

It's up to you, the city's best detective, to solve the case.

When you arrive on the scene, the police tell you what they know.

One:

each house's owner is of a different nationality,

drinks a different beverage,

and smokes a different type of cigar.

Two:

each house's interior walls are painted a different color.

Three:

each house contains a different animal, one of which is the fish.

After a few hours of expert sleuthing, you gather some clues.

It may look like a lot of information,

but there's a clear logical path to the solution.

Solving the puzzle will be a lot like Sudoku,

so you may find it helpful to organize your information in a grid, like this.

Pause the video on the following screen to examine your clues and solve the riddle.

Answer in: 3

2

1

To start, you fill in the information from clues eight and nine.

Immediately, you also realize that since the Norwegian is at the end of the street,

there's only one house next to him,

which must be the one with the blue walls in clue fourteen.

Clue five says the green-walled house's owner drinks coffee.

It can't be the center house since you already know its owner drinks milk,

but it also can't be the second house, which you know has blue walls.

And since clue four says

the green-walled house must be directly to the left of the white-walled one,

it can't be the first or fifth house either.

The only place left for the green-walled house

with the coffee drinker is the fourth spot,

meaning the white-walled house is the fifth.

Clue one gives you a nationality and a color.

Since the only column missing both these values is the center one,

this must be the Brit's red-walled home.

Now that the only unassigned wall color is yellow,

this must be applied to the first house,

where clue seven says the Dunhill smoker lives.

And clue eleven tells you that the owner of the horse is next door,

which can only be the second house.

The next step is to figure out what the Norwegian in the first house drinks.

It can't be tea, clue three tells you that's the Dane.

As per clue twelve, it can't be root beer since that person smokes Bluemaster,

and since you already assigned milk and coffee,

it must be water.

From clue fifteen,

you know that the Norwegian's neighbor, who can only be in the second house,

smokes Blends.

Now that the only spot in the grid without a cigar and a drink

is in the fifth column,

that must be the home of the person in clue twelve.

And since this leaves only the second house without a drink,

the tea-drinking Dane must live there.

The fourth house is now the only one missing a nationality and a cigar brand,

so the Prince-smoking German from clue thirteen must live there.

Through elimination, you can conclude that the Brit smokes Pall Mall

and the Swede lives in the fifth house,

while clue six and clue two tell you

that these two have a bird and a dog, respectively.

Clue ten tells you that the cat owner lives next to the Blend-smoking Dane,

putting him in the first house.

Now with only one spot left on the grid,

you know that the German in the green-walled house must be the culprit.

You and the police burst into the house,

catching the thief fish-handed.

While that explanation was straightforward,

solving puzzles like this often involves false starts and dead ends.

Part of the trick is to use the process of elimination

and lots of trial and error to hone in on the right pieces,

and the more logic puzzles you solve,

the better your intuition will be

for when and where there's enough information to make your deductions.

And did young Einstein really write this puzzle?

Probably not.

There's no evidence he did,

and some of the brands mentioned are too recent.

But the logic here is not so different

from what you'd use to solve equations with multiple variables,

even those describing the nature of the universe.

3

Answer these questions in your own words. Support your answers with evidence from the video.

01What are the five distinct categories of information the detective knows are unique to each of the five houses?
Sample answerThe detective is told that for each house, there are five unique characteristics: the owner's nationality, their preferred beverage, the brand of cigar they smoke, the interior wall color, and the type of animal they keep as a pet.
02What specific method does the narrator recommend for organizing the information, and why is it compared to Sudoku?
Sample answerThe narrator suggests using a grid to organize all the clues. The comparison to Sudoku is made because the solving process is similar; you use logic and a process of elimination within the grid to deduce where each piece of information belongs.
03In what way does the video suggest the real-life process of solving this puzzle might differ from the linear explanation it presents?
Sample answerThe video presents a very clean, step-by-step solution, but it acknowledges that a person actually solving it would likely face a much messier process. It mentions that solving these puzzles often involves false starts, dead ends, and a lot of trial and error, rather than following a single, clear logical path from the start.
04Despite casting doubt on the riddle's origin, how does the video ultimately connect the puzzle's underlying logic to Einstein's scientific work?
Sample answerEven though the video concludes Einstein probably didn't write the riddle, it links the puzzle's logic to his work by explaining that the skills used—like solving for multiple variables and using the process of elimination—are fundamentally the same as those a physicist would use to solve complex equations, even ones that describe the nature of the universe.
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Vocabulary

Vocabulary
These expressions will help you communicate more naturally about this topic.
Examples
To piece something together — to gradually understand a situation or story by using all the small pieces of information you have.
Usage note: this phrasal verb emphasizes the process of assembling disparate facts to form a complete picture. It's often used in contexts of investigation or solving complex problems, e.g., 'The detective pieced together the clues to identify the thief.'
A red herring — a fact or idea that is intended to be misleading or distracting from the real issue.
Usage note: this idiom is commonly used when discussing mysteries, debates, or complex problems where irrelevant information is introduced. Example: 'The detail about the time of the phone call was a complete red herring.'
To jump to conclusions — to make a judgment or decision about something without having all the facts.
Usage note: this is a common idiom used to criticize hasty thinking. In a logic puzzle, it's crucial not to jump to conclusions but to wait until you have sufficient evidence for each deduction.
It stands to reason that... — a phrase used to introduce a statement that is a logical conclusion from the known facts.
Usage note: this is a semi-formal discourse marker perfect for presenting a deduction. It adds a tone of certainty and rationality to your argument. For a more informal alternative, you could say 'It makes sense that...'
To follow a line of reasoning — to understand the series of logical steps or arguments that lead to a particular conclusion.
Usage note: this collocation is useful for discussing the process of understanding someone else's logic or explaining your own. You might say, 'I can't follow your line of reasoning, can you explain it again?'
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Decide if each statement is true or false. Correct the false ones.

01The video presents the puzzle as a brain teaser that was definitively created by a young Albert Einstein.
02The color of the first house is identified as yellow through a process of elimination after all other wall colors have been assigned to other houses.
03Following a specific line of reasoning, the detective pieces together that the Dane is the resident of the second house and drinks tea.
04The investigation culminates with the discovery that the thief is the Swede residing in the fifth house.
05The narrator suggests that intuition is not a significant factor in solving logic puzzles, which rely purely on deduction.
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Complete the sentences with words from the box. One word is extra.

Word bank
01The detective spent all night the various clues, hoping to form a coherent picture of the crime.
02The suspect's elaborate alibi turned out to be a complete , designed to distract the investigators from the real evidence.
03It's important not to based on a single piece of evidence; we need to consider all the facts before making a decision.
04Given that she was the only one with a key, it that she was the last person to leave the office.
05I couldn't quite follow his , as he seemed to make several logical leaps without explaining his thought process.
7

Choose the best answer based on what you heard in the video.

01According to the video's step-by-step solution, how is the location of the house with blue walls determined?
02What specific reason does the narrator provide to suggest that Albert Einstein was probably not the author of the riddle?
03What crucial constraint prevents the green-walled house from being placed in the first or fifth position?
04Which of the following is NOT mentioned in the video as a technique or reality of solving complex logic puzzles?
8

Language of logic and deduction

Connect the sentence halves to form logical statements about reasoning and problem-solving.

Match each item on the left with the correct item on the right.

Drag or click to match
Definitions
9

Discuss these questions with a partner. Try to use vocabulary from the lesson.

  1. The video demonstrates how a complex problem can be solved by meticulously following a line of reasoning to a single correct answer. To what extent is this model applicable to ambiguous, real-world issues like policy-making or interpersonal conflicts? Is there a danger that an over-reliance on pure logic can become a red herring, distracting from crucial emotional or ethical considerations?
  2. Think about the detective stories, mystery novels, or crime shows that are popular in your culture. How do the protagonists typically solve cases? Do they painstakingly piece together evidence like in the video's puzzle, or do they rely more on intuition, witness psychology, or even lucky breaks? What might this preference suggest about cultural attitudes towards logic?
  3. It stands to reason that in the age of AI and big data, our ability to analyze information is constantly tested. Reflect on a time you had to piece together information from various sources to make an important decision. How did you identify potential red herrings or resist the urge to jump to conclusions based on incomplete data?