Friday 6 April 2007

Find the "buck" over the weekend

While I was working as a temporary barista in Starbucks before I went to UK, someone told me this. It’s very interesting…

3 friends went to a hotel and rented a room. At the check-in counter, the receptionist said the room rate was $30 for a night. The 3 friends agreed and they each paid $10 for the room.

3 friends X $10 each = $30 for the room

After leaving the counter, the receptionist realised she made a mistake, and that the room rate was only $25 for that night. Therefore, she asked the bellboy to return the $5 which has been over-paid to the 3 friends.

$30 originally paid – $25 actual rate = $5 refund

As the bellboy walked to the room to return the $5, greed sets upon him and he decided to ‘steal’ $2 from the refund of $5 and thus, only $3 were refunded to the 3 friends.

$5 total refund – $2 ‘taken’ by bellboy = $3 refunded to the 3 friends

Are you able to follow? If you can't, scroll up and read again. If you still can't, take out your SPM cert and whichever grade you get for Mathematics, over-write your grade with a capital “F”… stands for F*cked-up.

Back to the story…Those 3 friends happily accepted the $3 and they divided the $3 among themselves. Naturally, each of them got $1 each. Since each of them originally paid $10 for the room, their individual cost is now $9.

$10 paid per person – $1 refunded per person = $9 paid per person

Now that the 3 friends have been refunded $1 each, they each only paid $9 for the room (as shown above). This would mean, the total amount paid by them is $27.

3 friends X $9 each = $27 paid

Since the 3 friends now effectively only paid $27 in total, and the bellboy has ‘stolen’ $2, this would only amount to a total of $29.

$27 paid + $2 ‘stolen’ by bellboy = $29

Now… Ladies and genitalman… the room rate was originally $30 and those 3 friends originally paid $30 (i.e. $10 each). But…$27 paid + $2 ‘stolen’ by bellboy = only $29!

Where is the missing $1?

This is not a trick question.


Ah Yun Wong said...

It's not 27 + 2 = 29, where's the missing dollar?
It's "27 - 2 = 25 !

The story continues :

The next night two different men showed up and wanted to rent a room together. The clerk again charged them $30, so they paid $15 each. Then the clerk hit his head and remembered he screwed up again, so gave the bellboy $5 in singles to return to them. The bellboy decided to pull the same trick, but this time he pockets $3 and gives the guests only $2, one apiece.

So now both men paid $14 each, and the bellboy took $3. That's $31. Aha! We found the missing dollar! ;-)

Clever ?

Anonymous said...

I'd really like to know where the missing dollar went. It's mind boggling! *head spinning from thinking too much*

Wickedsa said...
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Wickedsa said...
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Wickedsa said...

will I get a prize if I answer this?haha.
this is an account question.I wonder if pookyma knows this, since he's taking should ask him to answer this:p

You can't minus the 1buck that had given back to them.
what you have to count is the real value of the thing they consumed.Initially it's 30bucks(nilai yang betui betui ialah tiga puluh!!!), so 10bucks each is the real value they'd paid.
9buck is not the real value.
cannot take 9bucks to count how much they had consumed.

nilai is not value is value, price is price.that's why I am using the word "value" instead of "price".

Honestly, I am just spitting out what I know about this account question.if I am wrong,correct me and forgive me.

p.s: I am not an account student too :p

Sam said...
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Sam said...

3 friends X $9 each = $27 paid

That would mean they've overpaid already right?


So yeah, it should be 27-2=25 said...

Hehe, ive heard this one before.. its a good one, Zewt!

But actually, all the money is accounted for, its just the way the question as asked that makes it confusing.

There is still $25 in the cashier, and $1 with each of the friends ($3) and $2 with the bellboy. = $30.

They paid $9 each, so thats $27, -$2 with the bellboy, so thats $25 in the cash register. Not the other way round! Hehe..

if u say $27 + $2 then u get $29, but thats wrong.. it should be $27-$2=$25.. quite like an optical illusion of a magician.

for all the maths whizs, here is the proof...





TingTitLei said...

wah so many long long theories. mine is very simple

25 / 3 = 8.333

8.333 + 1 = 9.333

3 X 9.333 = 27.999

so.. 27.999 + 2 = 29.999

do i get a prize for posting the simplest solution ? haha

TCA Student Council said...

ah... no wonder i cannot answer.. failed maths since p3... hahaha

Cocka Doodle said...

I say all of you are wrong lah...!

In the first place, there is no such thing as a $30 room unless its some rumah tumpangan along Jalan Chowkit or Jln Alor.

Then again, rumah tumpangan don't have bell boys. ...and if the Ah Pek in his old pagoda singlet overcharged you $5 for your room, you can be sure the barger won't refund you.

Anonymous said...

haha!!! cocka doodle comment sounds damn logic! RM30 room you expect got bellboy service meh? kekeke..

baggie said...

erm... mine goes like this..

rm30 / 3 = rm10 per person (so wat)

rm30 - rm5 clerk returning =
rm25 total paid

bellboy stole rm2 =
rm25 + rm2 = rm27

each one of friends got rm1 x 3 =
rm27 + rm3 =rm30

So ma RM30 lor... doe wan bring the 3 ppl in ka-ka-cau-cau bahagi bahagi...

LOL.. dunno, simply say wan ah.. kih kih kih...

Anonymous said...

it's midnight here, and I had a TIRING but fun day!

I can't think of anything to answer the question right now!

But I REALLY like LINKEN LIM's theory! lol

nice one!

kyh said...

lol! interesting yet pening kepala.

nice one!

Jazzi said...

The missing buck is in Zewt's pocket...


Got asked this ages ago, the traditional answers are boring...

I still think it's in Zewt's pocket...

Anonymous said...

the 'problem' lies in the statement 'the 3 men paid rm9 each for the room.'

simply put, this is not true - a purposeful misdirection. in actual fact, if the bellboy pockets rm2, the cost of the room then 'becomes' rm28 (not rm27) and the 'price' that each man paid is in fact rm 9 1/3, thus accounting for the missing dollar :)

again, just b/c each man received rm1 back does not make the 'cost' the room (10-1)x3=27. the cost of the room is actually 30-(the pocketed)2 = 28


please applaud nat for this answer. he's so clever! :)

Wennn said...

HI Zewt.. hope over from Siwwypig's blog... See wat's cooking... sekali I saw it's MAths... Aiyoooo pening... but like reading all the answers given.... Good maths good maths

ManaL said...

Ditto to many of u above. I 1st solved it the same way as politikus. And i agree that those statements may get confusing.

Bellboy nih dah biasa buat kerja kira2 ni yea...

Terra Shield said...

Very interesting question... unfortunately the possible theory i could think of has already been posted above.

Nora aka Anon Fm Miri said...

Just dropping by to tell you tat I'm back home. Tot I can meet you in KL tat day but it was really a pleasure meeting politikus. I'm out of words. She's so sweet tat I've forgot to pass her the "black and white peper" Hopefully next trip cud meet both of you.


The Author said...

Okay, i am a Math idiot. I don't know the answer =/

Alliedmartster said...

Adios anon, till we meet again!

Zewt.....talking bout accountants...
3 accountants wanna be were in the same room waiting for their turn with the interviewer...
First candidate from Singapore goes in...
Candidate: Good morning, sir. Its a privilege to be called in for this interview. My certificates are here,and I am ready to take on this challenge.
Interviewer: Very well, but before we proceed. Can you answer this question?
What is 1 + 1?
Candidate: (in an instant...) 2!
Interviewer:Thank you, we will call you if you are shortlisted...
Candidate:?? (wondering if she said anything wrong??)

The second candidate, an Indian is then called in...
Candidate: Sirrr, Very good Morning. I would like to inform you sir that I graduated top of my class, and here are my certificates.
Interviewer: Very well, but before we proceed, can you answer this questions? What is 1+1?
Candidate: 2! Sir, I know this very well, the answer is 2!
Interviewer:OK, if that is your answer, we will call you if you are shortlisted.

The third candidate, a Malaysian, strolls in and closes the door.
Candidate: (walks straight to the chair and seat down) Hello brudher!
Very hot outsidelah....
Interviewer:?? Excuse me, but this is an interview, and I believe you are here as a candidate??? (looks in disgust!)
Candidate: Aiyah..sorry, but I have to get straight to the point. So do you have any questions??
Interviewer: !! Yes, you are suppose to answer a question before we even consider you!!
Candidate: Ok, ok, what is the question??
Interviewer: What is 1 + 1??
Candidate: (looks around the room shiftily...) Hey, 1 + do you want it to be???

....guess who got the job??

narrowband said...

I swear to God I was asked this exact same question just exactly three days ago. Guess where and when? It was during a job interview. The interviewer asked how good my math was. I said I'm actually quite good. But this question made me feel damn stupid. And no, the answer was never revealed. But some of your commentors have provided some answers - which I find valid... Anyway it's too late now - I think I failed to impress the interviewer afterall :(

Now Zewt, if only you had written this post earlier...

Eli James said...

I'm gonna ask my parents this. ;P Kekeke.

the witch's broo said...


it's a trick question.

-- won't even attempt to answer.
but i am waiting with bated breath to know what it is!

Anonymous said...

haha, i heard this question long time ago, but never really know the answer. Now thanks to all the commenter here, now I know :)
And by the way, my husband enjoyed this quiz too, and he was laughing like mad when I explained to him the answer from Cocka Doodle :)

wkhai said...

actual money paid = $9 x 3 = $27

actual price for room: $25
unknowingly tipped the bellboy: $2

all monies accounted for!
no missing dollar :P


money in the cash register: $25
money in bellboy's pocket: $2
money back in each friend's pocket: $1 x 3 = $3
TOTAL: $30

no missing dollar :P

ahjohn said...

if this is happening in Malaysia, we should report it to the police.
They would spend 1,000,000 dollars to set up a R&D team to find out where that 1 dollar went.

you know why?

that is our education system

may said...

this is one which I've come across so many times, and yet I've never really been able to solve it. and even when someone tells me the answer, I forget it all over again!

ahjohn said...

at a second thought i would think reporting to the police would be bad. the whole 30 dollars would go missing straight away.

anyone wonder why?

Huei said...

*pengsan from thinking*

*pulls hair frantically*

damn good one!! omg i think i cant sleep tonite liaoo..i must know the myth!!!! hehehhe

lovegoddess said...

the hardest things are the simplest eh????

quit thinking dy....just hate figures....failed maths in highschool.

i like Russ's solution & cockadoodles's theory though :)

Mrs Chong said...

the other day when i was at my friend's place playing cards, her aunt asked us this ques. Dunno she really want to ask us or just wanna take our mind off the cards and let her win since she lost quite a lot already. And after she gave us the answer she wanted us to pay her rm5 each. Hah, I guess cause she lost. But we refused to give her since we did not ask for the answer..kaka.. anyway, itz the accounts way. Many of them have explained earlier, so yea, not gonna repeat it again here..

flaminglambo said...

zewt, email me.

I need you for cyber sex. :P

ahjohn said...


when is your next blog coming out?

forget the maths. give us the chemistry...
like SPERM + OVUM = xxx


Horny Ang Moh said...

Ah Zewt!!I have being reading 5 time ready still don't known/can't find the missing RM1-00. I have read all the above coment some seem to be the answer. So CAN GIVE THE ANSWER? I don't like to go to bed still figuring out where is the missing RM1-00.. BTW mine mathe very very poor wan, fail all the way from primary one up to form five!!!

Anonymous said...

My friend asked me that when I was in form 5. I couldn't figure it out. And she never told me the answer!! Oh the agony. Haha!

hcfoo said...
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hcfoo said...

The problem actually occurs at your calculation of the total refund of RM5 in the 3rd stage of the calculation.

The RM2 (taken by the bellboy) shouldn't be deducted from RM5 again. Same goes to the RM1 refunded per person which is deducted from RM5 too. It is because you have actually deducted RM5 during the 2nd stage (RM30 - RM 5 = RM25 if you rearrange the math sentence).

So if you add back that RM1 to the 'over deducted' RM2 (-RM2), you will now be missing RM1.

If you actually work that problem backward, each person gets a total of RM3 + RM2 stolen by the bellboy + RM25 room rate you will get RM30. No money is actually missing.

Acrelaine said...

hmph, no ashes... no.... no P as well.. if he ever has one, i'll make a tablet out of it...

rachel said...

sorry lah... haven't have the time to go through your whole archive. anyways, some of your post are quite informative. :>

Purple~MushRooM said...

The equation in the question is wrong. There's where the confusion comes into play.
Like Linken Lim said,
It's not 27 + 2 = 29
It's 27 - 2 = 25

In other words, 25 received by the hotel + 2 taken by the bellboy = 27 (this is what is paid)

Love is in the air bakes said...

seriously...u were a barista too??? :D

zewt said...

Dear All,

I am very impressed with some of your answers... particularly the one from Cooka!!!

Anyway, this question is actually a question to test whether a person can stick to a particular notion.

You see... many of you justify that you can account for the 27 paid and you then from there you can deduce that 27-2 = 25. But that was not the question. The question is where is the missing 1 buck?

The main thing is that 30 were paid originally but in the end, only 29 can be accounted for. Not asking how you can deduce from 29 to the actual charge of 25, or from 27 to 25. I hope you all know what I am saying.

In order to answer the question, one has to locate the missing 1 buck ....


Try to deduce that despite the refund, you can still account for 30 bucks.

As such, the most accurate answer was given by.... TTL, Calvin's wife and hcfoo.

Anyway... the reason given to me was even more ridiculous.

And anyway(again), this question is not exactly a maths question... it's a question to test the ability of the human brain to stick with the notion of argument.

P/S: Yes Charmayne, I worked as a barista before.

P/S/S: AhJohn hahaha... i like your explanation too, on how much they will spend on research but no answer. but you know what? you totally went out of topic... failed! :P

zewt said...

linken lim - i must say yours a very good explanation. so your answer is that the missing 1 buck was magically teleported to 2 friends who will come the next day eh? haha!

rinnah - it is... the wonder of maths :)

baby sa - hmmm... i am a bit confused about your answer woh.

Sam - aiyah.. refer to my reply above... u ran out of topic.

russ / politikus - i like your answers too.

TTL / Calvin's wife - smart la smart la.

big rice - hahahaha!! so you're in IT la.

Cooka - you really the king of ham sup lo la hahahahaha

april - you can join cocka... haha...

Lash - thanks for trying... sorry for the midnight stress.

kyh - got take panadol?

Jazzi - 1 buck also i wanna steal meh?

Wenn - yeah, must thank them for layan-ing me hehe...

Manal - it's meant to confuse ppl :)

Terra Shield - wah... sounds like an easy way out. ok ok... i trust you.

Anon Fm Miri - see ya next time brother.

Julie - no prizes for you then :P

alliedmaster - wahh... you totally went out of topic la.

zewt said...

narrowband - hahaha... the interviewer conned you... read my main reply above.

dienasty - what did they say?

witch's broo - hahaha... another easy way out.

mich - so what was your husband's explanation ah?

wkhai - this is a good attempt... but then you are just listing all the transaction... but when you link some of the items up... they will only tie to 29.

Ah John - refer to my main reply above. anyway, the police will ask for more than 30 bucks.

may - actually, there is no real answer.

huei - still for hair left or not? hahahaha....

lovegoddess - another cocka's fan here eh?

ping ping - there are many version of answers... i think every answer is a real answer. haha...

flaminglambo - mailed you already. eh... i am not gay ok? hahahahaha... sex with your wife not enough? hahahahahaha

Hor Ny - ya la... u go to bed think about something else, dont think about this one :P

hcfoo - good one my friend. welcome to my blog.

acrelaine - wahh... cruel!

rachel - oohhh... take your time. anyway, thanks for linking me.

purple mushroom - ran out of topic la... see my main explanation above.

Anonymous said...

As this relates to Accounting...I as an Economist had to seek help from the ACCOUNTANTS.....

cash in the system
hotel : $25
bell boy : $2
3 friends : $3

accrual accounting
hotel : $25
bell boy : $2
3 friends : -$27

Huei said... any proper solution anot wan??

economist..i know that's how u summarize it, but why..does that 1 buck go missing?? y???

*no more hair left to pull liao!!*


Maverick SM said...


This is always an interesting aspects of mathematics 101.

zewt said...

economist - that is like saying a half full glass... half empty.

huei - some of the answer already given it lor... the real answer i had... you may all laugh at me.... cos when ther person who asked me told me that... i felt like killing him

Maverick SM - maths 101? tak beberapa faham.

baggie said...

and which is???? wats the answer you got Zewt?

Anonymous said...

It has to do with the way you look at the situation. Are we going from A to B...or from B to A?

You took:
30 - 3 = 27
By subtracting RM3 we are taking the initial amount of RM30 and working to find out what is the ACTUAL cost of the hotel room? So by doing:
27 + 2 = 29,
We are actually wrong!
You can't add back the RM2 to get back RM30! We should be subtracting the RM2
27 - 2 = 25 (actual hotel cost)
(If you wanted to get back RM30 from RM27 you have to add back the RM3 you initially deducted!!)

Another way of looking at it is by taking the actual hotel cost and adding back RM3 and the stolen money to get the initial amount
27 +3+ 2 = 30


sadsarcasm said...

I read and reread and re reread the comments and none of them seems to be clear..Zewt..please just rewrite a post and tell us where the missing dollar is..If not, i will have to read the comments again..

zewt said...


Ladies and gentlemen,

Ok, before I proceed, I must say the answer given to me by the person who asked me is really stupid... but here goes...

30 - (3x9) - 2 = 1

Where is missing 1 buck? It's on the other side of the equation. When you look at the equation from one side, the other side remain unseen.

Refer back to the first comment by Linken Lim, that's another classic example of looking at things on one side of the equation.

(2x14) + 3 - 30 = 1

Not many people will understand it. My conclusion is... always look at things on from both side of the coin.

P/S: vegemaster, dont la so pissed... haha!