# Tag Info

Accepted

### 3 doors, three guards, one stone

No questions are required!
• 3,615

Simple:
• 806
Accepted

### Liar liar pants on fire

I think the answer is: I mean,
• 9,253
Accepted

• 4,274
Accepted

### Who robbed the store?

Two questions? The truth tellers that are not the criminal will simply answer "no". The liars that are not the criminal will know their answer would be "yes", so they also answer &...
• 77.6k
Accepted

### How many liars are in the room?

I am sure there are :
• 17.9k
Accepted

### The Second Hardest Logic Puzzle in the World

This solution works no matter what happens in the case of paradoxes or questions with ambiguous answers. First, ask: With this, A note: this problem is actually easier than it seems, because
• 147k
Accepted

### Who committed the crime?

Answer: Reasoning: And it fits the requirement of one truthful answer and one lie for each.
• 18.2k
Accepted

### Out of these 20 Doors, Which One Leads You to the Jackpot?

Plotting every answer's truth combinations would take a lot of room, so let's take a couple of shortcuts first: Assistant 2 is speaking the truth. There are no square numbers with 6 distinct divisors ...
• 77.6k

### The Knight never lies, the knave always lies, and the spy either lies or tells the truth

To start, A must be: Then, B must The means that C must
• 8,216

### Batman vs 4 villains

This answer is kind of cheap and relies on some technicalities, but here goes: First round, ask everyone: Next, ask everyone: Now, we have one person we know is either always lying or always ...
• 8,216
Accepted

### Ask one verbal question to figure out who is blind and who is mute among three persons

I think this could be an answer:
• 1,145
Accepted

### XKCD inspired logic puzzle

With two questions, you can ask for the first question: Based on the answer you'll know if they speak the truth or lies. If they're lying: If the they're telling the truth:
• 1,347

This results
• 30.3k

### Batman vs 4 villains

The answer is The reason is This will also work if And just for kicks, However,
• 579

### Knights and Knaves: What does C say?

A shortcut to get the correct answer, assuming that one exists, is to simply assume that A, B and C are all knights, and thus speak the truth. In this case, C will obviously answer "Yes." And since ...
• 3,219

### The thief, liars, and the honest

Even simpler solution, with no hypotheticals needed:
Accepted

### Find the identity of the four troll brothers

The mathematically minimum possible solution is: Credit to supercat and user1540815! I overlooked an important fact in my first draft. If the trolls stand in one line, there are 4 possible ...
• 2,201
Accepted

### Which day of the week is today?

Rewording their statements: Today is Monday. Today is Wednesday. Today is Tuesday. Today is not Monday, nor Tuesday or Wednesday. Today is Friday. Today is Wednesday. Today is not Sunday. We know ...
• 117k
Accepted

### You trolls, get out of my party!

Solution: This was about the same thing I said before. But now... See Trenin's answer for a different formulation of the same approach, in case that one is easier to understand. Previous attempt at ...
• 18.2k

• 7,498
Accepted

### Knights and knaves in Landilandia

Ask the man that spoke to you: Reasoning: For the follow-up question: Reasoning behind this:
• 10.5k
Accepted

• 136k
Accepted

### An Infinitude of Deceptive Devourers

Answer: Explanation: Consider two possible cases. Case 1 - the children used the "at least" convention: Let's consider two subcases. Case 1a - only a finite number of people ate cake Case ...
Accepted

### Batman vs 4 villains

At least half the time, Batman can get the order correct in only 4 questions. For certain sequences, it will take 5 questions. The Riddler's future answer would be "Yes", and since he answers ...
• 385
Accepted

• 77.5k
Accepted

• 35.6k