....... and as such, the king is giving you the opportunity to marry one of his 3 daughters.
All 3 of his daughters are identical in EVERY way, except for:
the youngest sister ALWAYS tells lies;
the eldest sister ALWAYS tells the truth;
the middle sister just randomly tells the truth and lies whenever she pleases.
Remember, they are identical in looks and everything else that matters, apart from the truth telling, etc.
The king allows you to ask one (and only one) of the sisters one question only. The only problem is, you don't know which of the sisters you're asking the question to. Now ideally you'd like to marry the truth teller; although marrying the liar wouldn't be too bad - at least you'd know where you stand .... you must avoid marrying the middle sister at all costs.
What one question do you ask, in order to avoid choosing the middle sister ??
Truth teller will point to liar. Liar will point to truth-teller and middle one (which you don't want) will choose one of the other two. Change it to "who is the biggest liar?" then. The OP says only avoid the middle one- truthful one and liar are fine.
There's a similar riddle about asking gnomes at a crossroad for directions then doing the opposite. I'm not sure about this question though. It's something along the lines of asking what her sisters would say or what their answer would be then doing the opposite but I can't think of the question to ask.
Which one of your sisters would your lying sister tell me tells the truth? eliminate the one who answers and eliminate the the one who the answerer indicates and choose the other one.
Sorry - don't get confused by "best answer- I clicked it by accident.
Sunny - if you ask the question to the liar - both the other sisters tell the truth (one more than the other, but they both tell the truth) you might want to modify your question.