the 30$ vs 29$ puzzle.
ghar...@oread.cc.ukans.edu
very old. I didn't even try to think about it because I didn't want to waste
my time. Any way here is the puzzle :
Three men went to rent a room in a hotel, they decided to take one
room. It was 30$ for the room, so each one paid 10$. Then, after they
went to their room, the owner remembered that the room was on special for
only 25$. So, he gave his servant 5$ and told him to give it back to his
three cutomers. The servant thought that he can some money off the 5$.
So, the servant decided to keep 2$. If the servant gave each customer 1$,
then each cutomer only paid 9$. Now, 9$ x 3 = 27, and 27$ + 2$(the money that
the servant took) = 29$. What happened to the last 1$. I know if you
calculate it in any other way, it will make sence. But, if you think about it
the way I just explained it, it does not make sence. If you solve it, please
send a mail message.
Happy thinking, Ralph.
Tom Magliery
> I don't know if any one ever heard this puzzle before, but it sounds
>very old.
Fancy that.
>I didn't even try to think about it because I didn't want to waste
>my time.
Hmm. What about ours?
To everyone: There's hope -- the FAQ will be posted again in a few
days.
mag
--
Tom Magliery ** Dept of CS ** 1304 W Springfield ** Urbana IL 61801 ** USA
Keith Kushner
: Three men went to rent a room in a hotel, they decided to take one
: room. It was 30$ for the room, so each one paid 10$. Then, after they
: went to their room, the owner remembered that the room was on special for
: only 25$. So, he gave his servant 5$ and told him to give it back to his
: three cutomers. The servant thought that he can some money off the 5$.
: So, the servant decided to keep 2$. If the servant gave each customer 1$,
: then each cutomer only paid 9$. Now, 9$ x 3 = 27, and 27$ + 2$(the money that
: the servant took) = 29$. What happened to the last 1$. I know if you
: calculate it in any other way, it will make sence. But, if you think about it
: the way I just explained it, it does not make sence. If you solve it, please
: send a mail message.
Each customer paid $9. Of the $27, $25 went to the owner and $2 to the
servant. Expressing the question as you did makes no sense.
Chris Cole
This question is in the rec.puzzles Archive:
==> logic/29.p <==
Three people check into a hotel. They pay $30 to the manager and go
to their room. The manager finds out that the room rate is $25 and
gives $5 to the bellboy to return. On the way to the room the bellboy
reasons that $5 would be difficult to share among three people so
he pockets $2 and gives $1 to each person.
Now each person paid $10 and got back $1. So they paid $9 each,
totalling $27. The bellboy has $2, totalling $29.
Where is the remaining dollar?
==> logic/29.s <==
Each person paid $9, totalling $27. The manager has $25 and the bellboy $2.
The bellboy's $2 should be added to the manager's $25 or subtracted from
the tenants' $27, not added to the tenants' $27.
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THE rec.puzzles ORACLE
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rec.puzzles archive, and who will find your answer there if it exists,
or maybe compose an original answer if they are interested enough!
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RVES...@vma.cc.nd.edu
that's $52. where did the extra $22 come from?"
bob vesterman.
tom schmeling
<RVES...@vma.cc.nd.edu> wrote:
>one might as well ask, "the men paid $27. the shopkeep got $25.
>that's $52. where did the extra $22 come from?"
>
original, would not (I supsect) fool anyone. The first version seems
much more effective, psychologically speaking.
Jeffrey W Percival
Er, just a hunch, but isn't that why they call it a puzzle?
I guess that what I, too, find odd is RVESTERM's reasoning that
because one puzzle hinges on an arithmetic error, then all arithmetic
errors are puzzles.
How exciting and mysterious his life must be!
--
Jeffrey W Percival (j...@larry.sal.wisc.edu) (608)262-8686
RVES...@vma.cc.nd.edu
do you always insult people you don't know for no discernable reason?
i've got to tell you, that's just so cool, man.
i did not post what i posted to suggest that "where did the extra
twenty-two dollars come from" was a puzzle.
i posted what i posted to show anybody who might be having a tough
time with the $29 puzzle a different way of looking at it; a way
where the mistake is blatantly obvious, instead of more subtle.
bob vesterman.
tom schmeling
<RVES...@vma.cc.nd.edu> wrote:
>In article <1993Sep15.2...@sal.wisc.edu>, j...@sal.wisc.edu (Jeffrey W
>Percival) says:
>>
>>In article <1993Sep15.2...@scott.skidmore.edu>
>>tsch...@scott.skidmore.edu (tom schmeling) writes:
>>>In article <93257.1620...@vma.cc.nd.edu>, <RVES...@vma.cc.nd.edu>
>>wrote:
>>>>one might as well ask, "the men paid $27. the shopkeep got $25.
>>>>that's $52. where did the extra $22 come from?"
>>>>
>>>What I find interesting is that this version, though equivalent to the
>>>original, would not (I supsect) fool anyone. The first version seems
>>>much more effective, psychologically speaking.
>>
>>
>>Er, just a hunch, but isn't that why they call it a puzzle?
Very clever. Perhaps I didn't make my point clear. The question
is _why_, when the two formulations make the same error, the first
is regarded as a puzzle and the second would be regarded only as a
stupid mistake. As Bob notes below, the answer is that in the second
form, the mistake is obvious, but to me it is an interesting question
why _this_ mistake is "obvious" and the mistake in the original
formulation is not.
>>I guess that what I, too, find odd is RVESTERM's reasoning that
>>because one puzzle hinges on an arithmetic error, then all arithmetic
>>errors are puzzles.
The puzzle forces the puzzled to add $2 to $27 when she should
subtract it, but is it an arithmetic error or a conceptual error?
>>How exciting and mysterious his life must be!
>
>do you always insult people you don't know for no discernable reason?
I have to agree with Bob. Jeffrey completely misread his statement and
then posted a gratuitous insult based on that misreading.
Jeffrey W Percival
>I have to agree with Bob. Jeffrey completely misread his statement and
>then posted a gratuitous insult based on that misreading.
No insult intended, but my apologies anyway.
I read Bob's comment as from someone who'd seen this so many times
that he'd forgotten why it's confusing. Indeed, Tom used the word
"equivalent" in comparing Bob's example to the puzzle, and then went on
to show why they were in fact *not* equivalent.
I do understand the use of exaggerations to clarify puzzles (changing
Monty's door count from three to a million is a good example), but
I submit (respectfully) that Bob's assertion that "one might as well ask"
is still wrong. One might *not* as well ask what Bob did, else it's
not a puzzle.
Now we're down to quibbling about the semantics of "equivalent", but then
again, this *is* the group that thrives on mutual misunderstanding... :-)
David Alpert
In article <1993Sep13...@oread.cc.ukans.edu>, ghar...@oread.cc.ukans.edu writes...
> I don't know if any one ever heard this puzzle before, but it sounds
>very old. I didn't even try to think about it because I didn't want to waste
>my time. Any way here is the puzzle :
>
> Three men went to rent a room in a hotel, they decided to take one
>room. It was 30$ for the room, so each one paid 10$. Then, after they
>went to their room, the owner remembered that the room was on special for
>only 25$. So, he gave his servant 5$ and told him to give it back to his
>three cutomers. The servant thought that he can some money off the 5$.
>So, the servant decided to keep 2$. If the servant gave each customer 1$,
>then each cutomer only paid 9$. Now, 9$ x 3 = 27, and 27$ + 2$(the money that
>the servant took) = 29$. What happened to the last 1$.
You can't calculate this way. The bellboy is taking his $2 as negative money
(money paid by the men) from positive money (money given to the men.) This is
subtracting from a deficit, something you can't do. Say they paid the $30, and
then the manager gives them back $5. So now the manager has $25 and the men
have $5. _Then_ they give the bellboy $2. So, the men have $3, the bellboy
$2, and the manager $25. Now try that with the bellboy taking money for
himself like in the problem: First the manager has $30. Then he gives the $
to the bellboy. So the manager has $25 and the bellboy has $5. Then the
bellboy gives $3 to the men. The men have $3, the bellboy has $2, and the
manager has $25. So why doesn't this work the way the problem is set up?
Well, you can't say each paid $9. That would mean they gave $27 to the bellboy
+ manager, which works out. The add the money they didn't pay (they got for a
refund.) The problem says they pay thje manager + bellboy $27 dollars, and
plus the money the bellboy kept (you're counting it double) is $29.
--
"The t-test rocks the house."
- Grant @ GENE.LAN.2