Can you solve the temple riddle Dennis E. Shasha
You’ve found the hidden switches,
evaded the secret traps,
and now your expedition finally stands
at the heart of the ancient temple
inside The Lost City.
But as you study the inscriptions
in the near total darkness,
two of the eight graduate students
accompanying you
bump into the alter.
Suddenly, two whisps of green smoke
burst forth
and the walls begin to shake.
Fleeing for your lives,
you come to a room you passed before
with five hallways,
including the one to the altar
and the one leading back outside.
The giant sandglass in the center
is now flowing,
with less than an hour before it empties,
and the rumbling tells you that you don’t
want to be around when that happens.
From what you recall of your way here,
it would take about 20 minutes to reach
the exit at a fast pace.
You know this is the last junction
before the exit,
but your trail markings have been erased,
and no one remembers the way.
If nine of you split up,
there should be just enough time
for each group to explore one of the four
halls ahead and report back to this room,
with everyone then making
a run down the correct path.
There’s just one problem;
the inscriptions told
of the altar’s curse:
the spirits of the city’s King and Queen
possessing intruders
and leading them to their doom
through deception.
Remembering the green smoke,
you realize two of the students
have been cursed.
At any time,
one or both of them might lie,
though they also might tell the truth.
You know for sure that the curse
didn’t get you,
but you don’t know which students
can’t be trusted,
and because the possessed students
may lie only occasionally,
there is no guaranteed way to test
them to determine which are cursed.
Can you figure out a way to ensure
that you all escape?
Don’t worry about the possessed
students attacking
or otherwise harming the others.
This curse only affects
their communication.
Pause the video now if you
want to figure it out by yourself!
Answer in: 3
Answer in: 2
Answer in: 1
The first thing to realize is that since
you know you aren’t possessed,
you can explore one of the halls alone.
This leaves eight students
for the remaining three paths.
Sending groups of four down just two
of the paths won’t work
because if one group came back split
two versus two,
you’d have to guess who to trust.
But splitting them into one pair
and two trios would work every time,
and here’s why.
The possessed students might lie,
or they might not,
but you know there are only two of them,
while the other six will
always tell the truth.
When each group returns to the hall,
all of its members will either give
the same report
or argue about
whether they found the exit.
If a trio returns in total agreement,
then you know none of them are lying.
With the pair,
you can’t be sure either way,
but all you need is reliable evidence
about three of the four paths.
The fourth you can figure out
using the process of elimination.
Of course, none of this matters if you’re
lucky enough to find the exit yourself,
but otherwise, putting everything together
leaves you with three possibilities.
If each group gives a consistent answer,
either everyone is telling the truth,
or the two possessed students
are paired together.
In either case, ignore the duo.
If there’s only one group arguing,
both others must be telling the truth,
and if there are two conflicts,
then the possessed students
are in separate groups
and you can safely trust the majority
in both trios
since at least two people in each
will be truthful.
The temple collapses behind you
as greenish vapors
escape from two of the students.
You’re all safe and free from the curse.
After that ordeal,
you tell your group
they all deserve a vacation,
and you just happen to have
another expedition coming up.