@Justifiedboredom What was the point of mentioning your grades, etc? Do you think anyone cares, or did you just want to gloat instead of simply saying that you got it right.
I am a A - Level Mathematics student (as well as other subjects) and have recently passed my GCSEs (including a B in Maths) and i got this correct, im so glad :)
I would like to play all of your games and puzzle, but I'm Italian and I can't manage to understand everything you say in your videos. That's also because of you accent :(
well I assumed it was going to be the 3 And D you had to turn over. so i was only half right. I knew it was 2 cards but the 2 I had chosen to turn over only 1 was correct.
at first i was like 3 of them...thats because I missed the part that a card has a letter and a number. I thought that the letter K couldve had a D on the back.
Um for the alcohol problem it never says that the hoodie guy buys an alcoholic drink so technically i think the answer should be 1 since you never said that the hoodie guy buys alcohol
the whole answer is wrong...u just need to check the 7...."which card do you have to turn over to determine the validity of the statement?" ..the answer is 7....because assuming the question was correct, the 7 would prove it and if it was false the 7 would disprove it...
the whole snwer is wrong...u just need to check the 7...."which card do you have to turn over to determine the validity of the statement?" ..the answer is 7....because assuming the question was correct, the 7 would prove it and if it was false the 7 would disprove it...
@grande1899 That depends on what the survey stated for the definition of the word "mathematician"... Or maybe they gave only one second to answer the question?
i thought to myself, if it says a D then you have to check the d card, but if the 3 card doesnt show a d, dont touch it, the k and 7, well, your looking for a letter, and the k is already shown, so check the 7, and i got it right! :D
I got it. I read about this kind of problem in Scientific American Mind magazine. What gets most people is that they tend try to solve problems by trying to show what is true instead of what isn't. In this case, we need to preclude the possibility that 7 could have a D on the other side which would invalidate the conjecture. This kind of thinking or problem solving is what scientists and detectives do every day. It is a powerful thing to keep in mind when working on any kind of problem.
surely you would need to check all 4. before you bash me of and ignore this hear me out.
although the statement is an IF and THEN question; IF either of the middle two cards had a D on the other side then the statement would immediately prove to be false. and for a statement (im assuming a conjecture is the same as a statement as i am unsure of its absolute meaning) to be proven true, for the same as a formula, it must be true always with no exceptions
@Paradoxx211 ahh sry, i just thought it through again and your right, simply because of the added information of a letter and a number being on the other side. the K becomes irrelevant and the 3 is irrelevant due to your explanation IF and THEN.
Singingbanana, when you brought up the example of the four men at the bar, you said that we have to id the hooded man, but since he isn't drinking alchol, or anything else for that matter, he doesn't have to be id, just like the coke drinker. Just saying
Cool puzzle, would have been better if he had mentioned that all cards have a number on one size and a letter on the other, but maybe that's just me over thinking it lol. I thought that the K could have a D on the back making it false so you would have to look at three cards, but that's only if you can have two letters together.
My 1st instant guess was to pick the D and 3. but then, after thinking about it for about 15 seconds, I thought "If d does have a 3, then the 3 will have a d, so we don't need to check the 3, Rather the 7"
I'm 14,getting a C+ in math, and I'm smarter then a mathematician. :D I feel proud.
No matter what number the k has behind it, the orignal statement could still be true; every card with a D on one side could still have a 3 on the other side. Thus, it does not need to be checked, right?
I like this video. More riddles and logic problems, please!
I didnt really have the opportunity to check "how I did". You explained the answer as you were going. You really ought to tell us "when" so that we can stop the video
Eh? Can you translate into english, or make it clear what your point is, if you have one. Thanks
I said I got it wrong cause I forgot about the last card, then I said the statement was conditional, as someone said there was some problem with the question, but I totally disagree, it was very well posed.
What does my admitting to a mistake have to do with that? Seems you are just looking for an argument.
There was an earlier comment to which I think cms271828 is replying, which was wrong. I removed the wrong comment to prevent confusion. Looks like I added confusion!
so actually with the bar problem, assuming it's early enough in the daytime, all you need to do is card the guy who got the whiskey because the guy in the hoodie didn't even order a drink
and actually with the 4 guys at the bar, you also need to tell us what time they're there because even if you don't order an alcoholic beverage at a certain time, you have to be of legal age to even be in the bar
actually if you think about it, wouldn't you have to think about k for a second until you told us that if and when for the fact that the K doesn't matter if it has a 3 on the other side?
we need to check D because statment says that every "D" has "3" on the back side. we do not need to check "K" beause it will not help us prove anything even if there was "3" on it's other side. Same goes for "3" even if there is "D" on the other side we still can't prove that the statment is corect. But we do need to check "7" because there is obviously a letter and if that letter is not "D" than the statment is corect but if is than the statment is wrong.
My first reaction was to say turn over D and 3, but I thought about it for a second and then changed my answer to D and 7 before unpausing the video. I'm very surprised at the percentages you displayed. I hope that the great majority of educated people who missed this were simply blinded by arrogence and rushed through it.
Great illustration though. I enjoy your videos very much.
Other research reveals most people correctly realise "If A then B" requires us to check As and non-Bs (as opposed to As and Bs, the usual error), provided the question is posed as one to do with breaking social rules. Humans are fine at reasoning about those, but struggle with a logically equivalent problem without the same social character. This reveals a lot about the kinds of minds evolution has given our species.
At first I thought D and 3 but then I realized it was an if statement (before you said it!) and knew D & 7 were the answers. I love problems like this :)
Just read about this in Carl Zimmer's book 'Evolution'. Leda Cosmides and John Tooby used the results to support the view that our brains got big primarily to keep track of social complexities (an amplified version of chimpanzees knowing who they've groomed and who's groomed them). That's why, they say, people are better at the social version of the problem.
Not at all, the two questions are the same. The "if... then..." format is more commonly used in mathematics so I started with "every" to throw some people off.
hey man he just talks about the difference between 'IF' and 'IF AND ONLY IF'. You must read formal logic in wikipedia. But in logic, there are operators like AND, OR, IF, IF AND ONLY IF. They behave differently.
That's right, the implication is in one direction. If I had said "a card has a D on one side if and only if it has a three on the other" then the implication would have been in both directions.
However, there are some logics which try to better capture the standard usages of implies, like relevance logics. However I think classical logic is perfectly fine as long as you bear in mind that its purpose is to provide a model for deductive inferences, as there are other kinds of inferences (abductive, inductive, etc.)
I suppose that it is always confusing for most when they first study the truth table for implies. When I explain it I usually say that people should not worry about arguments like 'if the sun is a planet therefore godzilla exists', since even if the conditional is true that does not say anything about the truth of the antecedent and consequent (both false), and also even if the conditional in there is true that does not suffice to show the argument to be valid.
I think my comments haven't been altogether clear. What I meant to convey was that the truth table for implies isn't meant to capture standard linguistic usage, but to aid in modeling deductive inferences. So that if you know some proof to be valid you can discard row 2 and the interesting row is 1, which would also insure the argument is sound. You could have a valid argument with false premises and conclusion though, such as: all humans are dumb, top cat is a human therefore top cat is dumb.
I just did not think the problem through, I should have figured out that the entire universe of possibilities for that problem were those four cards. It was essential for the conjecture to be true that the row in the truth table which tells us that if the antecedent is true the consequent must also be true holds for that universe of possibilites. So, besised checking card D one must also be sure that any other card with a number different from 3 did not have a D on the other side.
i am smarter :D
il0velamp4 1 month ago
I wish they would have asked me this i would have gotten it correct.
MIT2004 1 month ago
WAIT,WHAT?
Powhentall 1 month ago
Maybe 57% of mathematicians give an answer to a generalized problem, not the acual cards displayed.
retepaskab 1 month ago
I'm clearly not smarter than mathematician but I got it right, lucky
eracless 2 months ago
@Justifiedboredom What was the point of mentioning your grades, etc? Do you think anyone cares, or did you just want to gloat instead of simply saying that you got it right.
ruster1971 2 months ago
Got it wrong ;o did not consider checking the 7 at first. Good trick!
TehMathWiztard 2 months ago
I am a A - Level Mathematics student (as well as other subjects) and have recently passed my GCSEs (including a B in Maths) and i got this correct, im so glad :)
Justifiedboredom 3 months ago
Comment removed
Justifiedboredom 3 months ago
This has been flagged as spam show
CHRISTMAS CASH MADE NOW!! > >FREE & EASY money in just HOURS!!
You can make FAST cash within just hours with this incredible program!! Go here….. TINA-WORKATHOME.WS
tinalb100 3 months ago
I said three, because I missed the part where you said each card has a letter and a number on opposite sides..
nietsnatsud 4 months ago
I would like to play all of your games and puzzle, but I'm Italian and I can't manage to understand everything you say in your videos. That's also because of you accent :(
palmomki 4 months ago
This has been flagged as spam show
check out my videos guys !!!!
IllusionsWillFoolYou 4 months ago
I don't get why this is a puzzle...It's simple logic to me..
BobbyFischer0000 4 months ago
well I assumed it was going to be the 3 And D you had to turn over. so i was only half right. I knew it was 2 cards but the 2 I had chosen to turn over only 1 was correct.
Rockwarrior2004 5 months ago
This has been flagged as spam show
I am smarter than 57% of the mathematicians! :D
Crabbi5 6 months ago
LOL! I am smarter than 57% of the mathematicians.
ThePassiveWatcher 6 months ago
at first i was like 3 of them...thats because I missed the part that a card has a letter and a number. I thought that the letter K couldve had a D on the back.
coolguy4488 6 months ago
could be in the first MATH1010 test in my Uni
lampuiho 6 months ago
i guessed 2
juplm4000 7 months ago
I got it!
MrYankeesfan413 7 months ago
Got it right!
PandeyNisheeth 7 months ago
I would have maximum forgotten to check the 7. Otherwise I got it right.
NiklasCR7Freestyle 8 months ago
>: (
Duodecillian 8 months ago
but pls tell me if im wrong :)
aleksr04 8 months ago
Um for the alcohol problem it never says that the hoodie guy buys an alcoholic drink so technically i think the answer should be 1 since you never said that the hoodie guy buys alcohol
aleksr04 8 months ago
57% of mathematicians should seek alternative careers.
mugwamp4 8 months ago
my teacher made this my final exam -_-
Yoshiki570 8 months ago
Comment removed
fragitza 9 months ago
@fragitza I thought it was pretty clear. Just pay attention to what he says, and you hear it... right? =|
Anyway, great video!
D3m190d 8 months ago
Comment removed
fragitza 8 months ago
@fragitza Hm, I guess I can hear pretty well, then. :P
But yeah, it was a very nice clip. ^^
D3m190d 8 months ago
the whole answer is wrong...u just need to check the 7...."which card do you have to turn over to determine the validity of the statement?" ..the answer is 7....because assuming the question was correct, the 7 would prove it and if it was false the 7 would disprove it...
dewaldjacobs86 9 months ago
@dewaldjacobs86 But there could have been another number other than 3 on the other side of the D so he had to check that too.
UlyssesKrunk 8 months ago
@dewaldjacobs86 Well, then you don't know if D actually has the number 3. As long as you don't turn D over, it could have any number other than 3.
D3m190d 8 months ago
the whole snwer is wrong...u just need to check the 7...."which card do you have to turn over to determine the validity of the statement?" ..the answer is 7....because assuming the question was correct, the 7 would prove it and if it was false the 7 would disprove it...
dewaldjacobs86 9 months ago
lmao I'm fifteen and i must be smart to know that the same domains cannot have different ranges, but the same ranges can have different domains.
PkmnTrainerJason001 9 months ago
really? only 43% of mathematicians got that correct?
J003S3PH 10 months ago
Hey, this puzzle sounds familiar!
singingbanana, have you ever read The Tipping Point before?
Phoenics100 10 months ago
Got it. Thank you. All of your video's are fun stuff. :)
stacischuler 10 months ago
It is tricky cos it seems very easy.If one thinks for just a while he will find the correct answer,if not he'll answer d and three instead.
asasasarap 11 months ago
yay i got it right, im the minority!
PS3Dragon4087 11 months ago
@Sind93 Professor Layton games are so awesome!
mathwhiz3 11 months ago
What are you on about? You DO need to check the K card, in case it has a D on the other side!
tomthecool 11 months ago
@tomthecool Ah wait, I just realised 0:11 ... You really could have made that clearer in your explanation!
tomthecool 11 months ago
This was actually quite easy
I guess it comes from playing so much Professor Layton XD
Sind93 1 year ago
:D at 0:59 i thought he was gonna slam his head on the blackboard ppphahahahah
:D:D
JuStInCrOsS1000 1 year ago
Should have ask the computer science engineers too ;) .
boumbh 1 year ago
Wow I can't believe even the majority of mathematicians didn't get this right. It's very easy.
grande1899 1 year ago
@grande1899 That depends on what the survey stated for the definition of the word "mathematician"... Or maybe they gave only one second to answer the question?
boumbh 1 year ago
i thought to myself, if it says a D then you have to check the d card, but if the 3 card doesnt show a d, dont touch it, the k and 7, well, your looking for a letter, and the k is already shown, so check the 7, and i got it right! :D
FredDeadz 1 year ago
that wasnt muth of a problem
JustMeHavingFun1 1 year ago
i think i am among the 18% that wasnt mentioned,because i noticed you only have 82% on the card at the end.
eXisentZ 1 year ago
@eXisentZ You don't add those numbers together.
singingbanana 1 year ago 5
@singingbanana I know. It was meant as a joke XD
eXisentZ 1 year ago
@eXisentZ Ah! Sorry. D'oh the internet.
singingbanana 1 year ago 9
@singingbanana relax,no need to apology :)
eXisentZ 1 year ago
@eXisentZ You misunderstand the last card. Its not supposed to add up to 100% its as follows:
10% of 100% of public got it right
29% of 100% of undergrads got it right
43% of 100% of mathmaticians got it right
make sense?
dewaldjacobs86 7 months ago
@dewaldjacobs86 i know that. it's meant as a joke xD
i did get it wrong too :P
eXisentZ 7 months ago
I f*cked up
weezinthejuice13 1 year ago
I got it. I read about this kind of problem in Scientific American Mind magazine. What gets most people is that they tend try to solve problems by trying to show what is true instead of what isn't. In this case, we need to preclude the possibility that 7 could have a D on the other side which would invalidate the conjecture. This kind of thinking or problem solving is what scientists and detectives do every day. It is a powerful thing to keep in mind when working on any kind of problem.
Haseeb2 1 year ago
Yay I got it right!
elizze6 1 year ago
I got it! Yes!!
TheAwesomeBrandon 1 year ago
Comment removed
wooperboy60 1 year ago
i'm not smarter than any mathematician. math is not my thing ... my brain doesen't handle numbers well ... but i do love your videos ...
agrumazescu 1 year ago
testalways(dot)com/2010/07/05/find-bugs-and-patterns/
testalwaysdotcom 1 year ago
Comment removed
xadamxful 1 year ago
U HAVE TO ID THE COLA DRINKER CAUSE IN ABOUT 1983 COLA HAD COKE In IT SO HAHAHAHAHAHa
ratedmini 1 year ago
you must check 3 because if there isn't a d,then its false
123456lvr 1 year ago
@123456lvr the statement says D:3 not 3:D
URZeroGravity 1 year ago
I got it right, but only after I reread the question; the first answer that popped in my head was wrong.
Desrathedemon 1 year ago
I got it right. :D
onpon4 1 year ago
surely you would need to check all 4. before you bash me of and ignore this hear me out.
although the statement is an IF and THEN question; IF either of the middle two cards had a D on the other side then the statement would immediately prove to be false. and for a statement (im assuming a conjecture is the same as a statement as i am unsure of its absolute meaning) to be proven true, for the same as a formula, it must be true always with no exceptions
please respond and prove me wrong! thanks
Paradoxx211 1 year ago
@Paradoxx211 ahh sry, i just thought it through again and your right, simply because of the added information of a letter and a number being on the other side. the K becomes irrelevant and the 3 is irrelevant due to your explanation IF and THEN.
cheers for the problem though :D
Paradoxx211 1 year ago
that was not a puzzle the anwser was given at the beginning
SNDVeteran 1 year ago
Did he say "the implication is in one direction" or "..isn't one direction" ??
funtube99999 1 year ago
Singingbanana, when you brought up the example of the four men at the bar, you said that we have to id the hooded man, but since he isn't drinking alchol, or anything else for that matter, he doesn't have to be id, just like the coke drinker. Just saying
namangreat 1 year ago
Cool puzzle, would have been better if he had mentioned that all cards have a number on one size and a letter on the other, but maybe that's just me over thinking it lol. I thought that the K could have a D on the back making it false so you would have to look at three cards, but that's only if you can have two letters together.
Does that make me part of the 90%? lol
Good video, Subscribed and 5* ^_^
AscianWalker 1 year ago
0:11
singingbanana 1 year ago 26
@singingbanana I need to listen better lol, thanks.
AscianWalker 1 year ago
@singingbanana lol, you totally owned him
J003S3PH 1 year ago
i guess i could have solwed the puzzle but i watched the video 'till the end
meat283 1 year ago
i got it but thats because i have no life and my life depends on math to function
Wanting333 1 year ago
My 1st instant guess was to pick the D and 3. but then, after thinking about it for about 15 seconds, I thought "If d does have a 3, then the 3 will have a d, so we don't need to check the 3, Rather the 7"
I'm 14,getting a C+ in math, and I'm smarter then a mathematician. :D I feel proud.
xNicksTuts4You 1 year ago
Yay got it right! Got it at about 1:30 :D
GammahooX 1 year ago
no :(
o0ocrizo0o 1 year ago
Comment removed
o0ocrizo0o 1 year ago
Didn't knew the answer
MindGamer9 1 year ago
Comment removed
jon1234700 1 year ago
dam got me
metalchango 1 year ago
well, if you think about it, then you have to check k too. Otherwise k and 7 could switch places and you'd get the same result, right?
LadyAlyss 1 year ago
No matter what number the k has behind it, the orignal statement could still be true; every card with a D on one side could still have a 3 on the other side. Thus, it does not need to be checked, right?
Error081688 1 year ago
I got it right!!
goodmanMD520 2 years ago
Lol, you have 1337.
SoaringDive 2 years ago
yes! i got it right
Materialgirl1021 2 years ago
Comment removed
aund123 2 years ago
1st q) 1, because it doesn't say every card with a 3 on one side has a D on the other.
Okay... I've just watched the end of the video, and I've realised I'm wrong. Sorry for the stupid comment...
olliebobs99 2 years ago
Yes! I knew reading Derren Brown: Tricks of the Mind wasn't a waste of time.
gemmaarrowsmith 2 years ago
Is this in there? Cool. Derren is ace.
singingbanana 2 years ago
I like this video. More riddles and logic problems, please!
I didnt really have the opportunity to check "how I did". You explained the answer as you were going. You really ought to tell us "when" so that we can stop the video
CogitoErgoCogitoSum 2 years ago 2
I'm learning, but thanks :)
singingbanana 2 years ago
The question is perfectly stated.. I messed up, I was too busy looking at cards 1 and 3 to notice card 4, so I said 1.
No, its conditional, if A then B, thats why we can ignore the 3rd card, as it will always give true if the back is a D
cms271828 2 years ago
And you think admitting to a mistake, but blaming it on absolutely nothing, proves what?
CogitoErgoCogitoSum 2 years ago
Eh? Can you translate into english, or make it clear what your point is, if you have one. Thanks
I said I got it wrong cause I forgot about the last card, then I said the statement was conditional, as someone said there was some problem with the question, but I totally disagree, it was very well posed.
What does my admitting to a mistake have to do with that? Seems you are just looking for an argument.
cms271828 2 years ago
There was an earlier comment to which I think cms271828 is replying, which was wrong. I removed the wrong comment to prevent confusion. Looks like I added confusion!
singingbanana 2 years ago
i got it
bkitty4lyf 2 years ago
I got it in less than a minute and I am not special!
I am smart if that is what you are implying.
: )
milfballs 2 years ago
so actually with the bar problem, assuming it's early enough in the daytime, all you need to do is card the guy who got the whiskey because the guy in the hoodie didn't even order a drink
sgtforge21 2 years ago
and actually with the 4 guys at the bar, you also need to tell us what time they're there because even if you don't order an alcoholic beverage at a certain time, you have to be of legal age to even be in the bar
sgtforge21 2 years ago
actually if you think about it, wouldn't you have to think about k for a second until you told us that if and when for the fact that the K doesn't matter if it has a 3 on the other side?
sgtforge21 2 years ago
its not pertinent to the conditional if the card has a d on it then the otherside is a 3.
ToPercent 2 years ago
pwned i got it rite and im 13 yrs old
animalcrossingguy128 2 years ago
I got it right, it's more of a logic than a mathematical problem, i wonder what percentage of logicians would get the correct answer?
I'm happy to be in the righteous 10% of the general public!
rohimbo 2 years ago
i thought you would have to check the d and the 3, but once you started taking out another sign you lost me lol
RickyAustinR 2 years ago
cool, i would have got it right but i forgot that each card had a letter on one side sooo i answered 3 you know?
acdc10133 2 years ago
i didnt really understand it...
ijrijrijr 2 years ago
Comment removed
jesuisfait 2 years ago
Damn, i assumed that because the 3 was there, there would be a D behind, because I assumed the inverse of the first statement.
Sandhand02 2 years ago
Exactly, it's an easy trap to fall into - for anyone! :)
singingbanana 2 years ago
i don't get something, what if the k had a d on the other side
sillybilly452 2 years ago
bacause each card has a number and letter
bscutajar 2 years ago
yeah i know. i rewatched it and realized it, i even put disregard that statement below it. lol
sillybilly452 2 years ago
completely disregard what i just said
sillybilly452 2 years ago
I failed to check the seven. Makes sense though.
RandomRandy420 2 years ago
I couldn't but my brother could to be fair he does study mathematics...
rotnakleugim 2 years ago
Excellent :)
singingbanana 2 years ago
This comment has received too many negative votes show
I got it right...well, I also have an IQ of 172, so it really wasn't a challenge. Got it right quick, too.
FCKEVRY1 2 years ago
Ah, 10th grade geometry. those were the days.
racerman33 2 years ago
The problem is that anyone that failed wont respond....
jimpa93 2 years ago
booyah. 10%
skateenjoi003 2 years ago
I got this right after the question was posed...
that's simple common sence
Dibs3332 2 years ago
ok here is how this works
we need to check D because statment says that every "D" has "3" on the back side. we do not need to check "K" beause it will not help us prove anything even if there was "3" on it's other side. Same goes for "3" even if there is "D" on the other side we still can't prove that the statment is corect. But we do need to check "7" because there is obviously a letter and if that letter is not "D" than the statment is corect but if is than the statment is wrong.
GioTMIP 2 years ago
Wo0t smarter than 47% of mathletes XD
RyanSnyder775 2 years ago
cool
jeudyfeo1 2 years ago
I'm smarter than 57% of the mathematicians woohooo!!!
Moorich 2 years ago
I'm one of the 29%!
dungeonmunky 2 years ago
Im in the 10% ^^
pigsareit 2 years ago
easy 10% of puplic
roman5hero 2 years ago
YAY! I am in the 10%!
FlloydOwnsAll 2 years ago
Well I got it, but I'm an engineering undergrad.
My first reaction was to say turn over D and 3, but I thought about it for a second and then changed my answer to D and 7 before unpausing the video. I'm very surprised at the percentages you displayed. I hope that the great majority of educated people who missed this were simply blinded by arrogence and rushed through it.
Great illustration though. I enjoy your videos very much.
TomStockman3 2 years ago
i'm twelve and i did it good it's just thinking logical!
victoriscool1 2 years ago
ha i knew i was smart i go it right
drew222100 2 years ago
NICE
R4mb0786 2 years ago
this is too confusing
CoolGuyChris233 2 years ago
huh? i have no clue what you are talking about
doyawanfrieswiththat 2 years ago
UH... WHAT
oscarrigomeleloy 2 years ago
What did the alcoholic drink thing have to do with the puzzle?
SiphonalToast 2 years ago
Other research reveals most people correctly realise "If A then B" requires us to check As and non-Bs (as opposed to As and Bs, the usual error), provided the question is posed as one to do with breaking social rules. Humans are fine at reasoning about those, but struggle with a logically equivalent problem without the same social character. This reveals a lot about the kinds of minds evolution has given our species.
PokemonGoldenOldies 2 years ago
I first thought about the D and the 3, but a little bit longer I thought about the seven, and I got the correct answer.
it's not hard, how could 43% of the matematicians got that wrong?
There are only 4 blocks, you could try your luck and get the correct answer
1MAKEDONEC1 2 years ago
Comment removed
apekattekatt 2 years ago
I also missed the seven :|
beatboxer04 2 years ago
i got D.... but then i guessed three...although while u were explaining the bar trick i changed my mind aout 3 and changed it to 7 so i dont know xD
CheatProjectDotCom 2 years ago
i got two aswell...
mariokart4life 2 years ago
but it doesnt say in the statment that a letter has to necessarlily have a number on the other side. ?
mowgli123456789 2 years ago
No, I did, at the start.
singingbanana 2 years ago
can someone explain why you dont have to turn all the cards round??
if the 'K' card had a D on the back of it then that would prove that the statement was false too surely???
help!!!!!!!
mowgli123456789 2 years ago
Each card had a letter on one side and a number on the other. So 'K' doesn't have a 'D' on the other side.
singingbanana 2 years ago
Missed the 7 ...great one.. improves teh thought process :)
gggg1111 2 years ago
Ah, I thought you only had to turn the D over, so I got it wrong. xD
LegendSaber 2 years ago
At first I thought D and 3 but then I realized it was an if statement (before you said it!) and knew D & 7 were the answers. I love problems like this :)
cmdtrigun 2 years ago
I got 2 :@
subtounpro 2 years ago
lol i got three coz i the first time through i didnt hear the letter 1 side and number the other so i thought ud have 2 check the k =( awell
spl0ck 2 years ago
I said "2 Cards" but I wasn't spasific enough.
Aaronneolover 2 years ago
Just read about this in Carl Zimmer's book 'Evolution'. Leda Cosmides and John Tooby used the results to support the view that our brains got big primarily to keep track of social complexities (an amplified version of chimpanzees knowing who they've groomed and who's groomed them). That's why, they say, people are better at the social version of the problem.
reclusivesage 2 years ago
i proudly take my place in the majority. ;)
mrhappyboss 2 years ago
well when you ask aquestion likethat people gets mathematicsmixed with real life problem, in real lifewedont say if and only if, we only use if.
iiimtf44 2 years ago
Nailed it. Another great problem though. I've got to try it on my friends,
mismag822 2 years ago
The question completly changes in the middle of the vid when he changes the rules to "if"
kkkhenders 3 years ago
Not at all, the two questions are the same. The "if... then..." format is more commonly used in mathematics so I started with "every" to throw some people off.
singingbanana 3 years ago
yus
Pizzscn 3 years ago
i got it right... as soon as i heard what i had to do the answer came right to me and i got it right.
2b2a 3 years ago
I Didn't Understand The Question, I Still Don't Understand It.
scottiez171 3 years ago
hey man he just talks about the difference between 'IF' and 'IF AND ONLY IF'. You must read formal logic in wikipedia. But in logic, there are operators like AND, OR, IF, IF AND ONLY IF. They behave differently.
iiimtf44 2 years ago
got it around just over 1 min.
seigfaroth 3 years ago
So from what I'm getting it doesn't matter if one has a 3 on it simply because of the way the question is phrased. Am I right?
redmon89 3 years ago
That's right, the implication is in one direction. If I had said "a card has a D on one side if and only if it has a three on the other" then the implication would have been in both directions.
singingbanana 3 years ago
However, there are some logics which try to better capture the standard usages of implies, like relevance logics. However I think classical logic is perfectly fine as long as you bear in mind that its purpose is to provide a model for deductive inferences, as there are other kinds of inferences (abductive, inductive, etc.)
3rdEarlRussell 3 years ago
I suppose that it is always confusing for most when they first study the truth table for implies. When I explain it I usually say that people should not worry about arguments like 'if the sun is a planet therefore godzilla exists', since even if the conditional is true that does not say anything about the truth of the antecedent and consequent (both false), and also even if the conditional in there is true that does not suffice to show the argument to be valid.
3rdEarlRussell 3 years ago
I think my comments haven't been altogether clear. What I meant to convey was that the truth table for implies isn't meant to capture standard linguistic usage, but to aid in modeling deductive inferences. So that if you know some proof to be valid you can discard row 2 and the interesting row is 1, which would also insure the argument is sound. You could have a valid argument with false premises and conclusion though, such as: all humans are dumb, top cat is a human therefore top cat is dumb.
3rdEarlRussell 3 years ago
It is an interesting puzzle, I hope you post more puzzles.
3rdEarlRussell 3 years ago
I just did not think the problem through, I should have figured out that the entire universe of possibilities for that problem were those four cards. It was essential for the conjecture to be true that the row in the truth table which tells us that if the antecedent is true the consequent must also be true holds for that universe of possibilites. So, besised checking card D one must also be sure that any other card with a number different from 3 did not have a D on the other side.
3rdEarlRussell 3 years ago
It's true that the card with the 7 needed to be turned over, I did not think it through. I thought of it as mere truth table for implication.
3rdEarlRussell 3 years ago