This has been shared massively around the social media and is a fairly interesting primary school puzzle. Now I tweak it a bit and retry it on you: Bernard’s birthday is on the 1st of April and on his birthday Bernard and Albert are trying to figure out Cheryl’s birthday (Albert and Bernard must lie in all three sentences or a part each, but Cheryl doesn’t lie!). So when is Cheryl’s birthday?
p.s. This tweak could have been a bit more interesting. The problem here is that at last Albert doesn’t know what kind of Lie Bernard is making. So yes it seems both June 18 as well as May 15/16 could hold them liar. The dates can be updated for both versions to satisfy a unique answer. Can’t think of it more now. Any suggestion?