Braingle: 'Spirit Search' Brain Teaser

Spirit Search

Logic puzzles require you to think. You will have to be logical in your reasoning.

Puzzle ID:	#9518
Fun:	(3.01)
Difficulty:	(1.52)
Category:	Logic
Submitted By:	IronMaiden980
Corrected By:	rashad

You are an expert on paranormal activity and have been hired to locate a spirit haunting an old resort hotel. Strong signs indicate that the spirit lies behind one of four doors. The inscriptions on each door read as follows:

Door A: It's behind B or C
Door B: It's behind A or D
Door C: It's in here
Door D: It's not in here

Your psychic powers have told you three of the inscriptions are false, and one is true. Behind which door will you find the spirit?

Answer

The spirit lies behind Door D.

If the spirit is behind Door A, then both B and D are true.

If the spirit is behind Door B, then both A and D are true.

If the spirit is behind Door C, then A, C, and D are all true.

If the spirit is behind Door D, then the statements on all the doors are false, except for that on Door B. This matches the rules, and therefore, the resort hotel spirit lurks behind Door D.
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Comments

jonnyonline Jan 16, 2003	theres a simpler way to solve this problem. if three of the statements are false then if any of the first three are true, it has to be behind door D by default. the other case is the fourth statement is true, which is contradicted by going thru each of the other statements (more than one true).
MysticGohan789 Feb 02, 2003	This one was easy
gooblah Feb 18, 2003	umm, i am not sure if this was easy or hard, I need to look at this sight when I am awake. =P
griphook Mar 07, 2003	Cool, real cool. I was wondering however if the psychic should be the one to guess which was the correct door . If he or she knew three of the statements were false, she would have known which three. That was just a thought. It does not take away anything from your enjoyable teaser. Keep them coming.
amorn01380 Apr 04, 2003	I'm the retard........well at least i don't like IRON MAIDEN
cee5222 Feb 03, 2004	dif spin on old riddle. too easy
BrenBeadSP Feb 03, 2004	It's cute and I enjoyed it, thanks.
Golfman072 Feb 03, 2004	Good teaser. Enjoyed it very much.
sockpuppet_frien Feb 03, 2004	easy....question though..if u have pyschic powers...cant u just tell which door it is behind??? j/w
XOLPLINKINPARK Feb 05, 2004	It was Awsome!!
neofreak29 Feb 03, 2005	cool one!
greebmaster-1 Feb 03, 2005	im not good at this kind of stuff
Jishter Feb 03, 2005	I liked this one a lot - though I read it backward (one false and three true). Anyway - a good puzzle. Thanks
Thundrax Feb 03, 2005	ummm, is it if Door D is the one, then inscription on Door b is true???
strangelove Feb 03, 2005	I knew that it would be easy, but still couldn't get it. I'ts a favorite for sure, I enjoy this kind of teaser.
i_am_blue15 Feb 03, 2005	it was a good teaser, all about logic. It reminded me of that thing with the two samurai, or whatever. And thundrax, it doesn't say that the door has to be true to have anything behind it.
qtpie9148 Feb 03, 2005	good one and easy i actually got it
fossil Feb 03, 2005	i enjoyed this one. it was kinda easy but fun. i rearly can solve the teasers so i liked this one alot.
fuzzie277 Feb 03, 2005	This was a nice little logic problem. Unfortunately, my reasoning had a flaw in it. Congrats, you stumped me!
94_8 Feb 03, 2005	So simple. I got this one in at least 45 seconds, but it was fun!
missredjeep Feb 03, 2005	Very easy but still cute.
saucyangel Feb 03, 2005	that was awesome! very easy (as many others have said) but still quite enjoyable to figure out! i like!
PBlover Feb 03, 2005	I liked this one alot!! very fun to do
mizgolf13 Feb 03, 2005	this was easy, but fun
sweetpeao4o3 Feb 03, 2005	that was weird
mudd-bunny Feb 03, 2005	this one was pretty easy, but i still ejoyed it a whole lot!
VLorion24 Feb 03, 2005	this was a nice riddle. it was kinda of tricky though.
Riki Feb 04, 2005	I enjoyed this one and I thought it was well written!
krabcat Feb 04, 2005	it was siple i got ot right a way
Get-o-sprstr Feb 09, 2005	the only reason why i got it was because i thought it said 3 were true and 1 was false, so i assumed, and that's how i got left over with door d. . i'm pretty sure i would've got it anyway. . real cute.
horse_luver Feb 13, 2005	Easy but fun. Good job. There's a fine balance between easy and dopey, but you achieved a simple teaser that was still good.
lmurray Mar 16, 2006	XIE XIE NI! (THANK YOU) IT WAS EASY, BUT IT MADE ME THINK FOR A MINUTE. TKS AGAIN.
smarty008 Mar 16, 2006	or just look behind each door great teaser anyway
bradon182001 Mar 16, 2006	Good teaser. Made you think and reason it out.
coachpisco Mar 16, 2006	A gasser!
RRAMMOHAN Mar 16, 2006	Interesting logic teaser. Fairly simple - got it! Thanks for making us think a bit.
churchlady Mar 16, 2006	Good job - but I couldn't get it. Thanks.
kman613 Mar 16, 2006	tricked me at first. good one
nathalia Mar 16, 2006	huh
iteachkids Mar 16, 2006	L TSA Fun. Thanx!
iteachkids Mar 16, 2006	BTW, I don't usually like the logic puzzles, but this one has entered my Hall of Faves!
rachellanders Mar 16, 2006	That was agreat teaser! The only reason I got it though was because I thought that "D" was the obvious one, because it said"It's not in here."
OldChinaHand Mar 16, 2006	Good simple logic often makes a good teaser. Good job.
octavian420 Mar 16, 2006	The easiest analysis is as follows: The statements on doors A & B are mutually exclusive and together describe all possibilities. Thus, one of them must true. Therefore C and D must both be false. Clearly if D is false, then that's the door you're looking for.
Fasil Mar 16, 2006	Octavian: I was about to say the same thing, but I think you worded it better than I could have. You sound like that guy from The Princess Bride.
TehIgnored Mar 16, 2006	This was easy.....but it was also very enjoyable.
vlerma Mar 16, 2006	Unfortunately today I'm not thinking very logically so this one went right over my head. Made a lot of sense to me AFTER I read the answer. Great job!
cherokeerose Mar 16, 2006	this one was very tricky..which i guess was your point...LOL...i got it right only becaused i guessed not because i used logic...LOL
Sara2009 Mar 16, 2006	I thought it was tricky and awesome. i liked it, its going into my faves.
rot10qt4life Mar 16, 2006	I LOVED it!! =0] my favorite so far!!!!
broken_dreams Mar 16, 2006	loved it!! took me awhile tho... although, couldnt you just look behind each door? i guess that kinda defeats the purpose tho huh? w/e. it was a great teaser.
doka13 Mar 16, 2006	Dude... Talk about twisting my brain around and confusing me. I had to read it like, 6 times b4 i finally figured out what it meant. I kinda feel dumb when that happens ... but, c'est la vie!
thimblenoggin Mar 16, 2006	Octavian- Thank you for saving me the trouble of trying to say that. Good teaser!
bowwows1 Mar 16, 2006	i only got it because Door D said its not here....so i assumed that it was there...
kashby Mar 16, 2006	I guessed d, but that is not why. That confusing. But I liked it ok.
kashby Mar 16, 2006	I guessed d, but that is not why. That confusing. But I liked it ok.
monkey93 Mar 16, 2006	I seriously got it right! WOW! It's just a trick question though, but AWESOME TEASER!
cartwheel_queen Mar 16, 2006	I GOT IT YAY
kikadez Mar 16, 2006	it was fun and easy
juicciefruit Mar 16, 2006	i thought that was quite entertaining and i still have to go back and figure it out but i love a challenge way to go
patpat553 Mar 17, 2006	WHAT???????????????
SandraB Mar 18, 2006	I didn't get it...
hottiegurl99 Mar 18, 2006	I got it, but it was easier to me because on the queen mary ghost tour they made us do that in the haunted dressing room, and i got it!! Great Teaser!
bluehawk Mar 19, 2006	BOO! Yes ,a great teaser. I got it.
BPKANERVA Mar 28, 2006	FUN BUT EZ
superben Jun 23, 2006	That was a good one! I got that one !!!!!!!!!!!
sumit Mar 16, 2007	Easiest way to solve - one of the statements 1 & 2 got to be true (both can't be false simultaneously) Thus, statement 4 is false and its behind D.
sumit Mar 16, 2007	i just read it - analysis made by me was already made by some one else and posted
grams60 Mar 16, 2007	this is a great teaser, and I enjoyed "trying" to solve it. I must be very logical, because I can never solve a logic teaser. when I see the answer, I think that I should have been able to solve it. it sees so easy when I know the answer. and YES I used to be blond, now I'm gray and white. keep up sending in logic teasers. I may get lucky and solve one.. :
kitty728 Mar 16, 2007	ok you got me ---at first i had this big long comment arguing that the answer could be door- A --til i re-read yr answer ---so you win... thanks for the brain work-out today ...i'll be-thinking it over while i'm stuck in traffic due to the on coming snow and ice... careful driving, gators..... later gators
katjojo Mar 16, 2007	Well written!!
bradon182001 Mar 16, 2007	This is still a great logic teaser. Got it right this time but it did take a minute to think it thru.
anion Mar 16, 2007	These have got to be the best types of teasers. I just love them. It takes me some time to figure out the answer but I did it. I really love logic teasers. Great job!!! Great teaser!!! Going to go to my faves for sure.
puttumup Mar 16, 2007	yawn
craniac Mar 16, 2007	I couldn't get enough coffee into my brain to even begin! So much easier to click "Show Answer."
cassiemark Mar 16, 2007	Too much thinking for me this early! Good job though. I would just open the door.........
phyllisa Mar 16, 2007	Good one, but I thought it was behind C.
Pizzazz2u Mar 16, 2007	A Totally Awesome teaser! Not too tough, yet easy enough to get one going in the morning hours! Keep up the terrific work!
FatHead Mar 16, 2007	That was cute! I often wonder how the logician can know what's true and what's not. To solve it, though, I just used the fact that A and B oppose one another, and not merely contract each other. Therefore, one of those is true, and C and D are false.
Quizme Mar 16, 2007	i guessed and still got it right!1
(user deleted) Mar 16, 2007	Check it out....the answer could also be A...Whoever made this brain teaser did not use all their brains.
builder Mar 16, 2007	julesfan, it can't be in A because then both A and D would be true
speedqueenkmw Mar 16, 2007	logical, I'm not
brihenn Mar 16, 2007	i figured it was behind door C because it could have been trying to tease hence the name brain teaser. good job!!!!!
soccermip337 Mar 16, 2007	Fun!!!!!!!!!!!!!!!!!!
jamy400 Mar 16, 2007	I finally got one right and understood it!!! Very clever and fun!!!
jabdr Mar 16, 2007	Yes, I have no logical abilities! But I liked Octavian's explanation, posted in 2006...I finally understood it then. Good one
breathesunshine Mar 16, 2007	It's good to know that I'm not brain dead afterall, I got it!
scallio Mar 17, 2007	Great teaser!
wordmama Mar 17, 2007	I usually don't get these, but this one I got!! Yay!! There's hope!!
wmrisok Mar 17, 2007	This was too easy, because I was able to figure it out in less than a minute. I wasn't aware of any "solving facts" until I read Octavian's concisely-worded statement., which will be useful in the future. I really oughta do more of these Brain thingies!
frozenrose_885 Mar 17, 2007	I had this type of question for a math challenge event at school I was the only one that got it.
oneheartbroken Mar 18, 2007	that was easy....but fun...i like the logic behind it....
Qrystal Mar 20, 2007	I thought this was a very cute variant on a familiar type of problem. There were also some very good explanations of how to obtain the answer very quickly, which was also a pleasure to see! I got it pretty easily, kinda like the way octavian described it. And clearly, some of us have seen Princess Bride before!! INCONCEIVABLE!!
Hungrygit Dec 07, 2007	I liked this one
westbrook Dec 12, 2008	I love these kinds of teasers
doehead Mar 16, 2010	Process of elimination made this pretty easy. But could be challenging for some who overthink it.
patiencewithaP Mar 16, 2010	Took me a minute but it was fun!
sunnybonghits Mar 16, 2010	Yep - I liked this one, even though it was a bit too easy. Obviously statement A or B had to be true, which means C and D both had to be false. If D is false, it's behind door D.
HoboCat Mar 16, 2010	That was a very simple, but great, logic puzzle by using assumptions and contradictions from those 5 statements. Good Job.
UptheHill Mar 16, 2010	BOO!!!
angelfinder Mar 16, 2010	It was too easy!! It's a child's game. No matter what the other choices were.. it's always behind the one that says it's NOT here. Didn't you learn anything as a kid.???
beyonce123 Mar 16, 2010	shut up stupid people, i u really dont like this riddle just keep it to yourselves. there's no point in making other people feel bad jut because you do. . also the whole point of log puzzle is that if you thik logically YOU SHOULD BE ABLE TO FIGURE IT OUT!!! ahem I PERSONALLY LOVED THIS TEASER. if you can't respect that then maybe YOU'RE the one who needs to grow up. If I can figure that out and I'm not even ourteen years old than you should take the time to use your brain (if you even have one) and THINK. A big thank you to everyone who posted a positive comment, that is why you have good karma.
beyonce123 Mar 16, 2010	sorry about the typos i=if jut=just log=logic
jcann Mar 16, 2010	Beyonce--even though what you said about the criticism may have some truth to it, the way you said it was just as bad or worse as those whom you were criticism. If you want to scold someone for a behavior, than you must demonstrate a better behavior. My problem with this site is the lack of respect for other people's opinions. Even though this teaser was not my favorite type, I respect the opinion of those who enjoyed it. You can't plaese everyone all the time.
jcann Mar 16, 2010	my typos- criticize instead of criticism and then instead of than.
jcann Mar 16, 2010	I mean "criticizing" Sorry!
FatHead Mar 17, 2010	I did it the easy way. Either Door A or Door B was telling the truth, but not both. Therefore, C and D were both lying, meaning D was lying, so it was D.
princess2007 Feb 22, 2013	Simple, easy, fun.
Babe Mar 16, 2013	I never ever get these kind of puzzles. Even after explanations they do not make sense to me. I am just a dummy, I guess.
cutebug Mar 16, 2013	If you unscramble your brain,this is very easy. Also this one has been repeated to many times. I'm sure HABS wiil agree with me.
allythebuterfly Mar 16, 2013	@Babe Don't worry I am totally with you. I did finally get it, but only after going through the process of elimination AFTER I had already seen the answer
auntiesis Mar 16, 2013	I love logic problems. This one was kind of easy, but still a good one.
HABS2933 Mar 16, 2013	Come now cutebug the teaser is only 10 years old. I do in fact agree. While at first glance it may have seemed complicated as soon as you began to eliminate statements, it became quite easy. IT may have taken me 90 seconds
thecatladycac Mar 17, 2013	So many players complain that teasers are old - I have been enjoying Braingle for several years now, and seldom run across one I have done before - There are constantly new people joining us that should have a chance to enjoy these that have been used in the past. You all should broaden the pot of choices by writing new ones to add to the collection (Yes, one of these days I plan on doing that!)
Allikat73126 Mar 18, 2013	EZ but fun