This is the answer posted on line. But it's wrong. There's a flaw in their step-by-step analysis. Trust me. I will give the correct answer later on to give everyone a chance.Originally posted by Goergs:
I think I got it. July 16th?
Are you going to tell us if we are right or just leave us hanging?
How did you come up with this conclusion?Originally posted by Pepperman:
It obviously isn't the 18th or the 19th, so can we start by eliminating those two options?
I am assuming they both have the list of 10 possibilities. So if she tells one of them the month, he still isn't sure what day. If she tells the other one the day, and it is either the 18th or 19th then that guy doesn't need to know anything more.Originally posted by TailgateTom:
How did you come up with this conclusion?Originally posted by Pepperman:
It obviously isn't the 18th or the 19th, so can we start by eliminating those two options?
You may be correct, but WWJD says you're wrong. At any rate, with the style that you wrote the above, and the strange style the original question is written in, I didn't follow any of your logic.Originally posted by TJ8869:
It's July 16 and Cheryl is a cock-tease.
Albert's first statement means he knows it's a month in which every possible date is a possibility in another month. That rules out all the May and June dates.
Bernards statement means that of the remaining options, he knows it is a date that is only possible in one month. That eliminates July 14 and August 14 and leaves July 16, August 15, and August 17 as the possible answers for Albert to deduce. He knows that it is July so it must be July 16. If it was either of the August dates then he would not know which one it was.
Posted from Rivals Mobile
Let's sort of re-do the dialogue here to make this easier to understand.Originally posted by What Would Jesus Do?:
Took me a while to figure this one out. Have fun.
Quoting myself here, but if ALBERT knows that Bernard cannot possibly know the birthday, that means ALBERT was not told May or June. He would know for sure there is no chance Bernard was told the 18th or 19th in that situation.Originally posted by Pepperman:
Let's sort of re-do the dialogue here to make this easier to understand.Originally posted by What Would Jesus Do?:
Took me a while to figure this one out. Have fun.
Albert knows which month. Bernard knows which day.
Albert's statement only tells us that it isn't the 18th or 19th. Correct?
What if Bernard was told 17?Originally posted by Pepperman:
Quoting myself here, but if ALBERT knows that Bernard cannot possibly know the birthday, that means ALBERT was not told May or June. He would know for sure there is no chance Bernard was told the 18th or 19th in that situation.
Once Bernard hears this, he knows that the month isn't May or June, meaning it has to be July or August. So at this stage, we have it narrowed down to just 3 possibilities.
Yep.Originally posted by Pepperman:
I am assuming they both have the list of 10 possibilities. So if she tells one of them the month, he still isn't sure what day. If she tells the other one the day, and it is either the 18th or 19th then that guy doesn't need to know anything more.Originally posted by TailgateTom:
How did you come up with this conclusion?Originally posted by Pepperman:
It obviously isn't the 18th or the 19th, so can we start by eliminating those two options?
This is the flaw in the online explanation. This does NOT rule out May.Originally posted by TJ8869:
It's July 16 and Cheryl is a cock-tease.
Albert's first statement means he knows it's a month in which every possible date is a possibility in another month. That rules out all the May and June dates.
Both kids have all 10 options before this begins.Originally posted by What Would Jesus Do?:
Took me a while to figure this one out. Have fun.
It does rule out May, b/c May has the 19, therefore if Albert were told May he could not know 100% that Albert was not told 19.Originally posted by What Would Jesus Do?:
This is the flaw in the online explanation. This does NOT rule out May.Originally posted by TJ8869:
It's July 16 and Cheryl is a cock-tease.
Albert's first statement means he knows it's a month in which every possible date is a possibility in another month. That rules out all the May and June dates.
But it does rule out June. So if Albert had been told that the month was June, he would know the answer. Since he tells us he doesn't know the answer at that point, that means June is not the correct month.
That, as it turns out, is enough info for Bernard to figure out the correct answer. And because he can figure out the correct answer with that fact (not June), we can figure out what number he must have been told.
Exactly. IF you could rule out May and June, then the arguments made on line and here by others seems right. But here is the actual list of dates after the first round:Originally posted by St. Louis Hawk:
Both kids have all 10 options before this begins.Originally posted by What Would Jesus Do?:
Took me a while to figure this one out. Have fun.
Albert - who is provided with only the month - initially can't know the birthday because each month has more than 1 date option.
Albert then says he also knows that Bernard also doesn't know.
If Bernard - who is provided with only the date - doesn't know, this must mean he wasn't provided with the unique dates of 18 or 19. So you can eliminate May and June.
Or that's at least what the online answer says. But I disagree with this - you can't eliminate the entire months of May and June, just the unique dates of May 19 and June 18. Unless I am missing something.
I think this is what WWJD is thinking of as the error.
I tend to agree with him, but I must be overlooking something because everyone else says the entire months of May and June can be entirely eliminated by Albert's first statement.
Assuming that the entire months of May and June can be eliminated, the rest falls into place as others have posted in this thread.
Haven't you built up an immunity to it?
That's actually an interesting argument that works if you assume that Albert knows Bernard doesn't know (in the first stage) NOT because Bernard didn't already claim to know (which is the way I'm looking at it) but because he was given a month that rules out any possibility of Bernard knowing. A priori vs a posteriori knowledge.Originally posted by BABiscuit:
So Albert knows the month, and by knowing the month, he knows that Bernard cannot know the date. If he was given May or June, he would not know for sure if Bernard knew the date. The statement isn't that Bernard knows the date, the statement is Albert knows he doesn't know the date. Therefore, he must have been given the month of July or August. If it was July or August 14th, Bernard still wouldn't know, but he says he does know. If it was August, he still wouldn't know if it was the 15th or the 17th. Albert knows if Bernard could figure it out, it would have to be July 16th, because he wouldn't have been able to know for sure if it was July 14th.
+ rep
I didn't see you already posted the answer (Aug. 17th). I thought I won a prize. It took me about 45 minutes to get thru it. I don't follow the July 16th answer though.Originally posted by What Would Jesus Do?:
To summarize my new position, I'm now of the opinion that both answers could be correct - depending on whether you interpret Albert's knowledge in the first stage as a priori or a posteriori knowledge.
Does Albert "know" that Bernard doesn't know because Bernard has not
claimed to know the answer (a posteriori knowledge) or because Albert
got a month that rules out Bernard knowing the answer (a priori
knowledge)? The a posteriori knowledge interpretation leads you to
August 17. The a priori knowledge interpretation leads you to July 16.
So . . . better buy Cheryl a present for each of her 2 possible birthdays to be safe.
July 16th is the only possible answer.Originally posted by whatsup12579er:
So what is the answer?
That's the way they do it in Kenya.Originally posted by IMCC965:
Why doesn't Cheryl just tell Albert and Bernard her birthday? What a little bitch.
I got that much but my head starts hurting on the next step. I'm going to resign on August 17 and join up with the July 16 crowd. My error was bringing May back in after I had already thrown it out in step one.Originally posted by TJ8869:
I'm not sure why some of you guys are struggling so much with the May issue. If her birthday was any of the May dates then Albert would have known only that it was in May. As far as he knew, Bernard could have been told 15, 16, or 19. He could not know for certain that Albert did not know the date because if Bernard had been told the 19th then Bernard would have known immediately that it was May 19.
If it had been any of the dates in May then Albert could not have stated with 100% certainty that he knew Bernard didn't know the date.
As soon as Albert made that statement, Bernard knew it had to be either July or August.
Posted from Rivals Mobile
After a little over an hour of reading and re-reading the July 16th crowds logic and starting a couple posts supporting August 17, I am now fully on board the July 16th train. And my head hurts. I need a drink.Originally posted by at4iowa:
July 16th is the only possible answer.Originally posted by whatsup12579er:
So what is the answer?