BTS: Just a solution this time around.

This week, I’m just posting the solution to last week’s challenge. The next brain teaser will be published in late August.

Last week’s brain teaser is one that I found very challenging. Here is my answer and justification:

We know that Albert knows the month, and Bernard the day of Cheryl’s birthday.

We can immediately eliminate any dates whose day number is only found once; had that been the correct date, Bernard would have known. We can then also eliminate any months that feature those days in the list; they been an option, Bernard might have known the correct day. Since Albert says he does not know, May and June is out.

That leaves July 14th and 16th and August 14th, 15th and 17th. We can now eliminate both instances of the 14th; duplicates are at this point mutually exclusive; had that been the correct day, Bernard would not have known the date. That leaves July 16th and August 15th and 17th. Because there are two options in August, the correct answer must be July 16th.