# Can You Solve This Complex Riddle About Escaping A Cursed Temple?

Video: This one's a doozy in that there is a lot going on. The goal is simple, you need to escape a collapsing tunnel with a group of nine people (including yourself). It's all the other variables that confuse things. There are four potential exit tunnels but only one of them is actually the way out. Each tunnel is a 20 minute walk one way and another 20 minute walk back. You have an hour to get out. Ideally, you can send different groups into the tunnels and then meet back at the junction to know which way is the exit. But! Two of the people in your group may be lying (or may not be! you don't know if they are or who they are), so what combination of people do you send down the people to guarantee your group's exit?

Ted-Ed explains in the fun mind puzzle below. Consider the maths.

I haven't watched the video so I don't know if there is more to it or the answer is explained. But that is not hard.

9 people, Inc 2 liars with 4 tunnels 40 minute turn around.

Groups of 3 into 3 of the tunnels.
If all come back it's the forth tunnel.
If 2 groups come back it's the 3rd groups tunnel.
If only one or two people come back from a group assume they are the liars, and it's their tunnel

Only time it doesn't work is if the liars are willing to die, and get to a dead end and refuse to go back

Last edited 04/02/16 11:48 pm

You cant send 4 groups of 2, because you might get that freak combo of 2 liars, and end up getting two groups saying theirs is the exit.

So you need a canary to call out evidence of the liar. In your listing, even if both liars are together, the third person will veto their lie, and the real positive will have 3 people calling the truth.

If the liars are split into separate packs, there will be two groups saying theirs is the exit - one will be 2-1 saying it, other will be 1-2, with the group with 2 votes being the truth. So your 3 groups of 3 should work. The odd man out in each group is the key to figuring out where the liars are, all three cant be lieing.

If the liars are willing to die, there's not much you can do about it. Wasnt one of the conditions, and in effect they arent lieing if they arent talking, so I guess the intention is that all of them return. But let em die in that case, everyone that returns will be telling the truth and its dead simple to figure the exit.

I can't see the video where I am, but aren't you in one of the groups? Therefore you can rule in or out one of the tunnels yourself, it doesn't matter who is with you. So then it is the even easier problem of telling which of the other two groups has liars, if any.

Doesnt really change things, but yeah, you're in a group. What if you're a liar though, that effects the other groups. The solution has to be one where any one of the 9 can figure the exit, and that includes the possibility of you lieing.

Having 3 in each group means the odd one out guarantees things. If two are lieing about it being an exit, the third says otherwise, so the real group of three that finds the exit will all say its the way out. 3 people trumps 2 people.

If the liars are split, then two people will be saying the exit is theirs, so the answer becomes 2 people trumping 1. Or its 3 v 1 v 1. Either way, splitting into 3 lets you trust the majority.

You are the only honest one for sure.
The split is 2 down one tunnel, 3 each down 2 tunnels and yourself in the fourth.

When you return back, you can vouch for yourself what you found in yours.
You can verify the groups of three as their stories will not correlate if they contain a liar
You can infer the truth of the group of 2 by what you have from yourself and the groups of three.

Yaay! I got it!