15 Apr
2015
15 Apr
'15
6:02 p.m.
On 15/04/2015 22:49, meekerdb wrote:
I get June 17. If Bernard were given 16 as the date he'd be uncertain between May and July and Albert couldn't resolve them.
No, I agree with Warren that July 16 is correct. B is given 16 and is uncertain between May and July, as you say; that is why at first he doesn't know when C's birthday is. But once he's told that A knows B doesn't know C's birthday, he can eliminate May (because if A were told May, A wouldn't know that B doesn't know because for all A knows the date could be May 19 and then B *would* know). That's why at step 2 B says he knows now. (And then at step 3 A knows, because that sort of reasoning wouldn't work if B had been told 14 instead of 16.) -- g