Can you solve "Einstein’s Riddle"? - Dan Van der Vieren

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 brainteaser

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 is 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 smoke 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 Paul 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 tell yous 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.