Solution Riddle 2

SOLUTION RIDDLE 2:

When reading the problem statement , one can stay stunned and go blank. However, anyone who has a little experience in addressing problems of logic and learn how to use the basic logic, perhaps for being a faithful follower of this blog; ),  can reach the solution, since no it is an extremely difficult problem; however you have to combine various mental processes, so it is an excellent exercise for the brain.

Let the matter:

We have 10 dates, with 6 numbers we see that some numbers are repeated except 18 and 19. Albert knows only the month of the birthday of Cheryl, and Bernard only knows the number.

In the first comment of Albert, who remember who knows the birthday month Cheryl tells us that you do not know your birthday but know that Bernard (who knows the number but not the month) does not know either. Bernard could only know the birthday if he knew the number was 18 or 19, which are the numbers that are not repeated in the list given by Cheryl. For Albert knew that Bernard does not know the birthday, it should fall into a different month to appear with the numbers 18 or 19. We are then 5 dates, July and August:

-        14 and 16 July

-        14, 15 and 17 August

With commentary by Bernard indicating that after the comment of Albert already know the date of the birthday, we infer that the number of the date that he knows should not be repeated in the list above, then, of those five dates must discard dates there are any number to repeat, staying only 3 dates:

-        July 16

-        15 August 17

Now in the second comment of Albert (who knows Cheryl's birthday month) it says that from the comment of Bernard and also knows that date is the birthday of Cheryl. As he knows the month, the birthday should be the July 16 , as if it were the birthday in August would have no way of knowing if the birthday is on 15 or 17 August.