logic puzzle 4

Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates.

Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively.

Albert: I don't know when Cheryl's birthday is, but I know that Bernard does not know too.
Bernard: At first I don't know when Cheryl's birthday is, but I know now.
Albert: Then I also know when Cheryl's birthday is.

So when is Cheryl's birthday?

These are getting harder...

I see...

ok

This is very tricky...I will have think for a while...

They don't know the birthday at first, use this as elimination.

And Albert knows that Bernard does not know too. That is more elimination

The dates 18 and 19 only appear once in the given dates, so her birthday cannot be on May 19th or June 18th... otherwise Bernard would have known her birthday

So those two dates are eliminated....we are left with 8 dates

yea

Ok....so my mom figured it out....She insists that Cheryl's birthday falls on July 16th.

As the dates June 18th and May 19th have already been eliminated, so Albert must have been told  the months July or August....for him to know that even bernard doesn't know 

that leaves us with the dates-

july 14, 16

Aug 14, 15, 17 

now bernard says that he has figured out her birthday, so the date that he has been told, cannot be 14th because that is present in two months.....So that leaves us with the dates-

july 16

Aug 15, 17

Now at the  end, albert says that now even he has figured out her birthday.....

And remember, Albert has only been told the month, so he would not know her birthday if it were to fall in Aug......and finally we get the answer as july 16th

you know you got that from the internet

yes

yes

yes you are right, in your dreams

Uhhh

oh lol