No Knaves, No Knights
You have been awoken in an island full of people. A voice has been greeting your mind to certain information.
"All of these people surrounding you are jokers. I am a knight. You don't belong here, and I will help you get back to your world and your memory will return." said the voice.
Upon exploration, you find a secret underground basement, leading to 5 different portals. With knowledge, the voice tells you that one of these is the portal to your world.
You ask a random group of people about the basement. They respond with simple sentences.
Person 1: Person 2 is not lying.
Person 2: Person 3 is lying.
Person 3: Person 4, 5 and 7 tell the truth.
Person 4: The first portal leads to your world.
Person 5: Person 6 is lying.
Person 6: The third portal leads to your world.
Person 7: The fourth portal leads to your world.
Person 8: Only four of us are speaking the truth.
The voice in your mind tells you that Person 1 and Person 8 are speaking the truth.
Determine all of the people who are lying.
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The problem doesn't clearly state but assuming from past experiences of these type of questions, a knight always tells the truth and a joker can either tell the truth or lie.
The voice in your mind states that Person 1 and Person 8 are speaking the truth.
Person 1 states that "Person 2 is not lying" - which is true. So Person 2 is not lying.
Person 2 states that "Person 3 is lying" - which is true. So Person 3 is lying.
Person 3 states that "Person 4, 5 and 7 tell the truth" - which is false. So Person 4, 5 and 7 are all lying
Person 4 states that "The first portal leads to your world" - which is false.
Person 5 states that "Person 6 is lying" - which is false. So Person 6 is not lying.
Person 6 states that "The third portal leads to your world" - which is true. This is the portal we need to go through!
Person 7 states that "The fourth portal leads to your world" - which is false.
Person 8 states that "Only four of us are speaking the truth" - which is true. The question asks who is telling the truth. The voice in your mind originally stated that Person 1 and Person 8 are telling the truth so that's 2 people. Then, we have Person 2 and Person 6 who are also telling the truth. Person 8 said that four people were speaking the truth and it is in fact, true!
Our final answer is that Person 1, 8, 2 and 6 are telling the truth.