39 votes
Accepted

Winning chance in coins game with fixing

GoblinGuide's user avatar
21 votes
Accepted

Two prisoners and twenty marbles

Same number of nights as in PDT's solution but perhaps expressed in a simpler way.
Florian F's user avatar
  • 29.8k
11 votes

Two prisoners and twenty marbles

They can do it in 10 nights at least:
PDT's user avatar
  • 12.1k
8 votes
Accepted

Is it possible to fill an arbitrarily large hex grid completely given these rules? #2

I claim the answer is because
Deusovi's user avatar
  • 146k
8 votes

Is it possible to fill an arbitrarily large hex grid completely given these rules?

I claim that the answer is and here's why:
Deusovi's user avatar
  • 146k
7 votes

The Alien Snails Experiment

The problem seems a bit under-specified, but as written, it seems the only possible valid answer would be Furthermore:
NoeS's user avatar
  • 279
7 votes

Two prisoners and twenty marbles

Minimising worst case waiting time, one can not do better than the number of nights presented by others. One can not safely lower by one night, since the person going second then only has So with the ...
SE - stop firing the good guys's user avatar
6 votes
Accepted

Pole, rope, and chasm

With the edits in place Considering one has infinite rope:
PDT's user avatar
  • 12.1k
6 votes

Winning chance in coins game with fixing

This is not nearly as elegant as GoblinGuide's simple answer: https://puzzling.stackexchange.com/a/126192/1777 The probability of winning is always: Strategy: For any given N coins, there is: This ...
LeppyR64's user avatar
  • 13.5k
6 votes
Accepted

The Alien Snails Experiment

Answer The answer is: Solution Extended Example Reversing It is a testament to the cruelty of the ruler that going backward counts as a separate move. Otherwise:
geometrian's user avatar
4 votes

One vs many. Can white force a draw?

In figures (1a), (1b), (2a), and (2b), the white cells are empty and the red cells may or may not contain black pieces. The pattern continues in the obvious way out to the infinities. In figures (3a)...
geometrian's user avatar
3 votes

6 Water Glasses Upside Down

I've solved this for arbitrary values of $n$ and $N$ ($n \leq N$) where, $n$ = glasses to select per move $N$ = total number of glasses My method showed no solution is possible when $n$ is even and $...
Abhinav Anand's user avatar
2 votes

One vs many. Can white force a draw?

Partial answer for N=4
Retudin's user avatar
  • 8,601
1 vote

Two prisoners and twenty marbles

A strategy that can get below 9.8 turns:
Retudin's user avatar
  • 8,601
1 vote

Two prisoners and twenty marbles

The simplest solution for each prisoner (still 10 days). One optimization that can lead to 9 days in many (6814) cases. The best case scenario for this scheme is done in 6 moves without sacrificing ...
phatfingers's user avatar
1 vote

Two prisoners and twenty marbles

I think this will work. Maybe there's something I have not accounted for, let me know.
puzzledgear's user avatar

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