Fun Math Problem

So it's Hump day and you're bored, so here you go. A cool little math problem to kill some time



Yes this CAN be solved with just the information provided. I'll give you guys a hint after an hour or so if you are all still stuck. Have fun!

a reply to: PsychoEmperor

I saw this earlier and I was on the right track in solving it, but I went too fast and my answer was wrong. I feel good that I did figure out how to solve it. I should have checked my work, though...

It's an excellent brainteaser!

I'll say May 19...If i may

Edit: I see clearly know, with my Google

June 17

a reply to: PsychoEmperor

Is it just me or could there be an English lesson in here too...."At first I don't know when Cheryl's birthday is.." or is that part of the problem...wouldn't it be "didn't know".

a reply to: rockpaperhammock

haha yeah. It IS from Singapore. Didn't want to give that away so people wouldn't be tempted to just google the answer

BTW, May 19 and June 17 are not correct, sorry

HINT #1: Albert was told the Month and Bernard was told the Day BEFORE the conversation started.

Bonus Hint: 18 and 19 are the only two days not repeated

originally posted by: PsychoEmperor
a reply to: rockpaperhammock


BTW, May 19 and June 17 are not correct, sorry

Ouch! I was certain of June 17. Now, lunch is over and I have to go back to work.

a reply to: PsychoEmperor

19th of May

I have not used any mathematics to get this answer. I followed the contents of my abdomen. I wonder if I was right?

Ok Bernard knows the day which means its the 18th or 19th...if it was anything else it would be too difficult to deduce.

June 18th...but only guessed that cause someone said May 19th and was wrong. I don't see how they are deducing the month.


edit: haha ok wait i think i got it....its the opposite of what i just said...it cant be the 18th or 19th...thast why the other guy knows...im on the right track..give me a few


I think you have to assume that albert is a deduction wizard himself


Ok I think its July 16th but its possibly August 17th, possibly august 15th.

The reason is albert is deducing that if bernard knew it was the 18th or 19th it would be instantly solved...since there are no other competitors to those "days"...so albert figures out that it can't be in may or june because of that argument....so now how do we figure out the month...it has to be a day that doesn't repeat so I think that knocks off the July and August 14th...

thats where im at so far


Ok i solved it...its july 16th...if they said august..it would give two possibilities....i just googled it and i swear the answer read exactly like i typed hahaha...i swear i found the answer on my own haha.

This problem actually sucks cause you have to assume bernard and albert are both deducing and deducing at the right time...its the order in which they deduce which helps you find the answer...the hardest part is figuring out when they are deducing.

originally posted by: VictorVonDoom

Ouch! I was certain of June 17. Now, lunch is over and I have to go back to work.

Why go back to work when you can have fun with math

originally posted by: rockpaperhammock
edit: haha ok wait i think i got it....its the opposite of what i just said...it cant be the 18th or 19th...thast why the other guy knows...im on the right track..give me a few

"a few" granted, This is fun

worst math problem ever!

it's so ambiguous.

And i used to work with a Cheryl. her birthday was december 9th.

originally posted by: PsychoEmperor
a reply to: rockpaperhammock

haha yeah. It IS from Singapore. Didn't want to give that away so people wouldn't be tempted to just google the answer

BTW, May 19 and June 17 are not correct, sorry

HINT #1: Albert was told the Month and Bernard was told the Day BEFORE the conversation started.

Bonus Hint: 18 and 19 are the only two days not repeated

Your hint gave it away ..I never would have got it without this post ...the 18 19th are critical for the start and then adding it June 17th helped as well!

So to rewrite the problem Cheryl tells Albert its July and tells Bernard its 16

Albert stated he doesnt know and knows that Bernard can't know.

Albert deduces that Bernard wasn't told May "19" or June "18" cause those would be instant answers as there are only one of them. This eliminates 2 dates. But it also eliminates the months as well because....Bernard states that he didn't know...and Albert states that he knows Bernard doesn't know...so if he didn't know for a 100% fact there is no way it could have been May or June cause that would leave the possibilities of 19 or 18 being said.


Albert then deduces that Bernard knows only cause there are 3 possible dates then...July 16, August 15 and August 17...since if it was August Bernard would only be 50% sure but he is 100% sure...this means it has to be the 16th....July 16th.

June 18th?

a reply to: rockpaperhammock

Yep, you got it! Great explanation too

It's less a math problem than it is a logic problem. However, you use logic all the time to help you in math.

Too bad US schools are more interested in teaching social engineering and what kids should think than in teaching kids how to think. This is a classic example of how to think that a child then applies to other subjects and life in general.