A guy visits a house where three identical triplet sisters lived – Sarah, Sue and Sally. Sarah is the oldest one followed by Sue and Sally. The sisters decides to mock him for a while and let him figure out who is who. Due to their identical looks, he is not able to identify who is who and thus decides to ask them each of them a question.
He goes to the sister sitting on the left sofa and asks her, 'Who is the one sitting in the middle sofa?' He is replied by the girl, 'She is Sarah.'
Then he goes to the one sitting on the middle sofa and asks her, 'Who are you?' To this he is replied by her, 'I’m Sally.'
Finally he goes to the one sitting on the right sofa. He asks, 'Who is sitting on the middle sofa?' She replies, 'She is Sue.'
He is left puzzled after the three answers. He asks again and repeats for three times in total. All of the time, he receives different answers.
He only knows three things:
Sarah, the oldest one is a truthful person who never lies.
Sue the middle sister is a big liar who never tells a truth.
Sally, the youngest speaks both truth and lies.
Can you help him find out who is who?
Solution:
Since the answers were different every time, the first one cannot be Sarah as that would make the first one a liar. For similar reason, even the second one can’t be Sarah. Therefore, the third one must be Sarah. If she is Sarah, the middle one must be Sue which leaves the left one to be Sally.