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Forums - Website Topics - Can you solve this mind-boggling problem?

Materia-Blade on 14 April 2015
the-pi-guy said:

May 15, 16, 19

June 17, 18

July 14, 16

August 14, 15, 17

Albert knows the month, Bernard knows the day.

Albert knows that Bernard doesn't know the date, which means that it can't be in a month that has 1 possibility.  Because that means that Bernard has a chance at knowing the date.  

So May and June are out.  (18th and the 19th are one possibilities.)

July 14, 16

August 14,15,17

Bernard knowing the day now has the answer, which means that it can't be on a day that has the same number for two months.  So the 14th is out. 

July 16

August 15,17

Albert knowing the month now knows which day it is.  That means there is only one possible date.  So July 16th.  

Was really tempted to cheat, but didn't.  

But it could be interpreted that any number would mean bernard doesn't know the date. so it's really just poorly writen.



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darkshadow23 on 15 April 2015

Albert knows the month but not the day. But he knows that Bernard is not able to know. So that cancels out the months of May and June. Why? Because of June 18 and May 19. 18 and 19 are not found anywhere else, so if Bernard knows the day is 18 or 19 then he knows her birthday.

So we have left. July 14, July 16, August 14, August 15, and August 17.

Bernard now understands the above and this let him figure out what her birthday was. The only way that he can know the date is if there is only 1 number. So that means we can cancel out July 14 and August 14.

Now we have: July 16, August 15, and August 17.

Then Albert says that he now knows her birthdate, and since Albert only knows the month then her birthdate must be July 16.



theprof00 on 15 April 2015
darkshadow23 said:
Albert knows the month but not the day. But he knows that Bernard is not able to know. So that cancels out the months of May and June. Why? Because of June 18 and May 19. 18 and 19 are not found anywhere else, so if Bernard knows the day is 18 or 19 then he knows her birthday.

So we have left. July 14, July 16, August 14, August 15, and August 17.

Bernard now understands the above and this let him figure out what her birthday was. The only way that he can know the date is if there is only 1 number. So that means we can cancel out July 14 and August 14.

Now we have: July 16, August 15, and August 17.

Then Albert says that he now knows her birthdate, and since Albert only knows the month then her birthdate must be July 16.

u got it



Boutros on 15 April 2015

Why do I get July 16?

 

Edit: Oh that's right!



theprof00 on 15 April 2015
darkshadow23 said:
Albert knows the month but not the day. But he knows that Bernard is not able to know. So that cancels out the months of May and June. Why? Because of June 18 and May 19. 18 and 19 are not found anywhere else, so if Bernard knows the day is 18 or 19 then he knows her birthday.

So we have left. July 14, July 16, August 14, August 15, and August 17.

Bernard now understands the above and this let him figure out what her birthday was. The only way that he can know the date is if there is only 1 number. So that means we can cancel out July 14 and August 14.

Now we have: July 16, August 15, and August 17.

Then Albert says that he now knows her birthdate, and since Albert only knows the month then her birthdate must be July 16.

It should be said that it is because albert knows the month, that we can deduce it is the 16th. Albert can only know if his possibility had been reduced to one. And that only happens with july



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darkshadow23 on 15 April 2015

Yay! eyem smrat!



the_dengle on 15 April 2015

I saw this on Facebook earlier, worked it out in 5-10 minutes. It's not that complicated or poorly written (although there are some grammatical errors), just required a lot of thought.



theprof00 on 15 April 2015

The hangup that most people will find in this problem is actually a higher level reasoning problem.
Most people get caught up on trying to figure out why albert and bernard know, instead of simply taking their word as fact.



t3mporary_126 on 15 April 2015

Well I guess I had enough internet for today.



Hynad on 15 April 2015
theprof00 said:
The hangup that most people will find in this problem is actually a higher level reasoning problem.
Most people get caught up on trying to figure out why albert and bernard know, instead of simply taking their word as fact.

That and the fact it is freacking 12:20am. -__-