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3 votes

Going around in circles

Speculative answer I firmly believe this is the answer but I cannot prove it because a key piece is missing, yet everything else lines up. If I shouldn't be posting a speculative answer like this ...
dvx2718's user avatar
  • 286
-2 votes

Going around in circles

What do you mean by letters? I'm not sure I get the point.
Josie's user avatar
  • 15
2 votes

Generalized knights and knaves puzzle

Sort of depends on exactly what a lie is, but here's a go. I ask the question to the leftmost guard: For the yes-no version, This general approach can be used as is or tweaked very slightly for most ...
kagami's user avatar
  • 369
2 votes
Accepted

3 doors guarded by 1 knight and 2 knaves

It is not possible to do it in 1 question, but can easily be done in 2. @hexomino proposes a solution with 1 question, but it does not work because: More generally, we cannot do it in 1 question ...
oak's user avatar
  • 136
0 votes

3 doors guarded by 1 knight and 2 knaves

You can ask one question to determine which guard is telling the truth. The question would be: "Point to the guard who is telling the truth among your companions." If you ask the guard who ...
Ahmed 's user avatar
7 votes

Nonconsecutive Anti-Knight Fillomino?

Parcly Taxel's user avatar
  • 7,790
9 votes

Nonconsecutive Anti-Knight Fillomino?

I've found out that it is not in anyone's interest to post excessive screenshots, so draw a grid yourself to follow my deductions. The number of solutions is Firstly, We now split into cases by ...
Culver Kwan's user avatar
  • 6,104
5 votes

3 doors guarded by 1 knight and 2 knaves

Without further restrictions on the types of questions that may be asked or further knowledge the guards have about each other, it is open to being achieved in one question as follows. Ask to Guard #1 ...
hexomino's user avatar
  • 137k
0 votes

The prisoners and the switch

Edit: It actually looks like this solution doesn't actually work, seeing as there's nothing preventing the same prisoner being called multiple times (thanks for pointing that out ConnieMnemonic). I ...
Blue Herring's user avatar
  • 1,493
11 votes
Accepted

66: Luftballons

Clue explanations: Dosun-Fuwari solve: And in the finished grids,
Deusovi's user avatar
  • 147k
1 vote
Accepted

Culture Fair IQ Test

Number 1 is Number 2 is Number 3 is Number 4 is
PDT's user avatar
  • 15.9k
2 votes

The prisoners and the switch

You could refine the probability of success using the Coupon-Collector's distribution and one bit of info to improve on that, While not part of the question:
kagami's user avatar
  • 369
3 votes

The prisoners and the switch

Obvious 1: Obvious 2: Strategy A:
Angel Sachse's user avatar
7 votes

The Room Of Tiles

I'll say that tile A "beeps" tile B if stepping on A first and then B produces a beep. If we need to be perfectly confident that our choice is safe: If we need a strategy to escape with ...
kagami's user avatar
  • 369
-1 votes

Leaders and Rulers

Edge case: A population of one. This one person is in charge of the whole population and of themself. If the only group is the whole population, this person is a leader. The premise states that "...
James Newton's user avatar
22 votes
Accepted

Leaders and Rulers

Consider the group consisting of everyone who is a ruler of at least one group. Like all groups, someone is in charge of it. If that someone is not in that group, they're its ruler, but that ...
xnor's user avatar
  • 27.4k
2 votes

Leaders and Rulers

(finite case; not sure if this extends to infinite case) Suppose not; then every person in the population has to be either a leader or a ruler (or neither). In particular, a leader cannot rule another ...
azi's user avatar
  • 543
1 vote

Logical Reasoning - Seating Arrangement problem

Fluorine has a good point about this being poorly phrased. The question as written means "absolute left and right, the one of an outside observer" (Fluorine). Note that the originator of ...
Bob Bixler's user avatar
1 vote
Accepted

Long Division when it is almost, but not entirely, wrong

Answer Solve Path It's easy to see that the last digit of the quotient is 0. The key point is the last digit of the remainder. Note that for a unique solution, the tens digits of the divisor and the ...
ACB's user avatar
  • 7,281
16 votes
Accepted

What's the one digit you can fill in this partially hidden Sudoku?

I think the answer is Indeed
Jujustum's user avatar
  • 3,865
5 votes
Accepted

Reconstruct a long division given less than a quarter of the digits, and all of those are wrong

The Answer Solve Path Consider the last digit of the quotient. Since it cannot be 1, it must be at least 2; and the last multiple of the divisor is 2-digit, which implies that the divisor is less ...
ACB's user avatar
  • 7,281
4 votes
Accepted

Communicate square on a 3-by-3 grid by flipping precisely one of 13 coins

We have 13 coin positions, which I'm going to give the following names (it doesn't matter which position is given which name, it can be selected arbitrarily as long as I and my ally agree on the ...
ais523's user avatar
  • 2,094
2 votes
Accepted

A Framework puzzle

Of course, we start with the 8-digit entry... Now, one slightly more advanced deduction than 'only one number fits here' is necessary. The solved grid is:
Deusovi's user avatar
  • 147k
8 votes

Torus Flow Free

As in Lezzup's answer (but more formally),
AxiomaticSystem's user avatar
13 votes
Accepted

Torus Flow Free

Below is the final answer: Explanation: I think the main question is, which color will go through the center column? Note that both B and C are adjacent to the cells connecting the center column ...
Lezzup's user avatar
  • 7,382
11 votes
Accepted

3-clue 5x5 Hidato

This one was tough! I managed to solve it mostly through trial and error. The vertical section between 16 and 22 is very constrained, because it needs quite a few sequences to pass through it, and ...
GentlePurpleRain's user avatar
2 votes

Solve the Alphametic: SOUNDS / WOW = ELK

Slightly different solve path:
AxiomaticSystem's user avatar
8 votes

Solve the Alphametic: SOUNDS / WOW = ELK

Let's start with the obvious. Next, However, All that's left now is Here's the final division problem: Putting it all together, we get our final solution:
juicifer's user avatar
  • 11.3k
12 votes
Accepted

Bare Bones – a semi-DIY crossword

Gladys is visiting: Completed grid: Across: Down Filling the grid: Finding the answer:
fljx's user avatar
  • 16.6k
11 votes
Accepted

New record for minimally clued 7x7 Hidato (now with 6 clues!)

Is this a race to the bottom? I solved the 8- and 7-clue puzzles before you edited to make the 6-clue one. (Edit: I also added a solve path for the 6-clue) 8-clue solution 7-clue solution 6-clue ...
Benjamin Wang's user avatar
2 votes

New record for minimally clued 7x7 Hidato (now with 6 clues!)

Here is an image with the solution to the 6 clue puzzle:
mathlander's user avatar
  • 1,261
5 votes
Accepted

Current record for minimally clued 7x7 Hidato (16 clues)

Solution: Step by step: 1: 2: 3: 4: 5: 6:
Beastly Gerbil's user avatar

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