Questions tagged [strategy]
A puzzle whose solution is a methodological plan of action for realizing a specific goal.
486
questions
-6
votes
1answer
91 views
Another how to kill 7 submarines
7 submarines are placed on an x, y grid - 0 to 111. They are located on whole numbered locations. Each submarine starts from any selected location with a given fixed speed and fixed direction, ...
6
votes
1answer
269 views
Russian Roulette (Redux!)
You are challenged to a game of Russian roulette with a six-chamber revolver, but you and your opponent are allowed to change the outcome of the game in different ways. Here's how the game will ...
1
vote
1answer
150 views
How to kill 7 submarines
7 submarines are placed on an x, y grid - from negative infinity to positive infinity. They are located on whole numbered locations. Each submarine starts from a location with a given fixed speed and ...
8
votes
3answers
1k views
30 fake coins out of 99 coins v2
Follow up question to my other question, but totally different methodology required.
You are given 99 coins which consists of 30 fake ones. You also have a digital balance scale with perfect ...
-2
votes
0answers
64 views
How does one cross the bridge? [duplicate]
There are two islands connected by a wooden bridge. The bridge can only hold two people at a time. There are four people on Island "A" and if they don't go to Island "B" they will get over run by ...
12
votes
3answers
2k views
Can you catch the thief?
This was a puzzle I recalled from university a couple of years back. I don't know what the original puzzle is but if someone knows it, please let me know so I can credit the source.
You are a police ...
11
votes
3answers
2k views
Find number 8 with the least number of tries
You and your friend plays a game. In this game, there are numbers written on the cards from 1 to 12 on one side (so 12 cards in total). The other side is blank. You can write anything on the blank ...
6
votes
3answers
275 views
Line segments inside a square
A set of line segments inside or at the edge of a square with side length 1 should be positioned in such a way,
that any straight line going through the square must touch or intersect at least one of ...
11
votes
2answers
2k views
Three knights searching for a princess in a castle
There is a castle with rooms arranged in a 4x4 square grid. The princess living in the castle sleeps in a different room each night, but always one adjacent to the one in which she slept on the ...
4
votes
1answer
314 views
Two knights searching for a princess in a castle
There is a castle with rooms arranged in a 3x3 square grid. The princess living in the castle sleeps in a different room each night, but always one adjacent to the one in which she slept on the ...
9
votes
1answer
155 views
A short but stimulating robot-control puzzle
The goal of this puzzle is to find a sequence of max 4 commands that will move the triangle through the maze and visit all colored squares.
Three types of commands can be used:
F0 makes the sequence ...
7
votes
2answers
257 views
Marbles on a Mancala Board
I would like to introduce an ancient African board game I've just invented.
Until someone comes up with a better name, it's called Marble Mancala.
The rules are pretty simple:
There are two ...
1
vote
1answer
156 views
Don't Fail MY Exam [duplicate]
A professor decides the following grading scheme in his class. After the final exam is graded, he keeps all the papers upside down on his table in a random order so that no student can recognise his ...
5
votes
2answers
266 views
The Wires Underground [duplicate]
There are ten wires that run underground across a river. Thus on each of the banks, there are ten ends of the wires. Unfortunately, given an end of a wire on this bank, one doesn't know which end on ...
4
votes
2answers
116 views
12 balls 1 scale with 4 groups
So, we all know the famous 12 balls 1 scale riddle. It has been here repeated many times, however, the provided solutions always start with splitting the twelve balls into three groups of four. This ...
2
votes
1answer
149 views
Sleeping Beauty Study at the Institute of Mad Science [closed]
You've been approached to assist in the furtherance of SCIENCE as a research subject at the Institute of Mad Science (local branch)!
The experiment you'll be involved with is called the Sleeping ...
6
votes
2answers
146 views
Positioning cards labeled with numbers from 0-9
Ann and Bob play a game. On a table there are 10 cards which are labeled with number from 0 to 9 each. Bob is allowed to change the position of the cards with a sequence of his preference. When he is ...
5
votes
2answers
119 views
A pile of chips involving powers of 2
Ann and Bob play alternately on a pile of chips. On each play, any number of chips, which is a power of 2 (including 1=$2^0$), can be removed from the pile.
Obviously the number of chips to be removed ...
6
votes
1answer
172 views
A pile of chips involving primes
Ann and Bob play alternately on a pile of chips. On each play, either 1, 2 or 3 chips can be removed except if the number of chips is a prime number. In that case either 1, 2, 3, 4 or 5 chips can be ...
10
votes
1answer
273 views
Reverse dots and boxes – Guess the last move
Alice and Bob are playing a game of reverse dots and boxes.
The players take turns adding one horizontal or vertical line of size 1 in one free spot on the grid (marked with light gray lines ...
2
votes
6answers
209 views
Two untrusted traders [closed]
I'm sure this has been asked before, but I tried searching and couldn't find it. I don't know the solution, and it is possible there isn't one.
There is unsavoury pirate and an unscrupulous merchant....
1
vote
1answer
106 views
How Should I Go About Answering Square Spin Puzzles?
The Square Spin series of puzzles is a bit abstract. There is quite a lot for newcomers to digest and getting started may be daunting. Even if you thoroughly read the rules and intend to attempt one ...
12
votes
1answer
652 views
Reverse dots and… cubes? - Snowflake edition
A Reverse dots-and-boxes puzzle inspired by @jafe
Albert and Robinson are playing a game of reverse dots and boxes.
The players take turns adding one plane in one free spot on the grid (...
8
votes
2answers
700 views
Reverse dots and boxes, swastika edition
Alistair and Roberta are playing a game of reverse dots and boxes.
The players take turns adding one horizontal or vertical line in one free spot on the grid (marked with light gray lines in ...
14
votes
2answers
692 views
Reverse dots and boxes
Alice and Bob are playing a game of reverse dots and boxes. The rules are simple:
The players take turns adding one horizontal or vertical line in one free spot on the grid (marked with light ...
18
votes
3answers
1k views
Where are the Wazirs?
A wazir is a fairy chess piece that moves like a rook, but can go only one square.
&...
6
votes
1answer
217 views
I'm a Proper Divisor
Ann and Bob are playing a number game. Ann starts with the number 60. Then she subtracts a proper divisor of 60 from it. Bob then takes the number Ann made and subtracts one of its proper divisors ...
8
votes
1answer
280 views
3D Chess - Stale NBA (kNight-Bishop Assault)
This is my very first chess puzzle. Any constructive feedback is more than welcome. Thanks!
Introducing 3D Chess!
To make things simple for the first time, we are using a $3\times3\times3$ ...
12
votes
4answers
522 views
Red and White Squares
There are two grid boards with the dimension of 9x9 and 14x14, consist of all white squares. You are supposed to color some squares with a red color on the conditions below:
In a board, if two square ...
6
votes
2answers
209 views
You Sign Me Right Round (Extended Edition)
I wanted to ask more questions about variations on This Problem. If you hadn't seen that one, check it out. It's required reading (and probably more fun).
In the original problem, these were the ...
8
votes
2answers
224 views
You Sign Me Right Round
This is a 9x9 grid, with a sign in the center cell like shown. You can add signs to this grid one at a time following these rules:
Each sign placed must point to the next sign placed
Placed signs ...
5
votes
1answer
197 views
Answered it badly…on purpose?
Teacher: You got a 0.
Miles Morales: Is that...failed?
Teacher: Listen. If you answer all questions on a multiple choice test randomly, you would get a 25%. This means the only way for you to ...
10
votes
1answer
276 views
A programming puzzle without code
The goal of this puzzle is to find a sequence of max 5 commands that will move the triangle through the maze and visit all colored squares.
Three types of commands can be used:
F0 makes the sequence ...
2
votes
1answer
114 views
Leveling up and Getting Items! v2
This is follow up question to Leveling up and Getting Items!
You are playing an online RPG game with 9 friends of yours (10 people
in total) and in the game, there is a 2-player dungeon where you ...
14
votes
7answers
684 views
10 coins, 3 of them are fake
Inspired by some great weighing puzzles here (This being one of my favorites), I just made another weighing puzzle - I'm not quite sure how difficult or easy this one is.
You are given 10 coins, 7 of ...
14
votes
4answers
2k views
Leveling up and Getting Items!
You are playing an online RPG game with 9 friends of yours (10 people in total) and in the game, there is a 2-player dungeon where you level up every time you enter and complete it. Only up to two ...
8
votes
1answer
695 views
I am caught when I was about to steal some candies
I am a eight years old boy, I love candies, but my mom does not want me to eat any more candies because I start to have black teeth :( but I still love candies so...
Today when I was about to steal ...
20
votes
5answers
5k views
Can you open the door or die? v2
This is the follow up question to my previous question
You wake up and find yourself in a very strange room with a single
door. You find a note on the ground surrounded by lots of cards:
...
11
votes
4answers
2k views
Can you open the door or die?
You wake up and find yourself in a very strange room with a single door. You find a note on the ground surrounded by lots of cards:
There are 66 green and 66 blue door cards on the ground. If you ...
11
votes
2answers
544 views
2019 gold coins to share
You and your friend has found in total 2019 gold coins in a treasure hunt. Since your friend found the place to dig up, he deserves a bit more gold than you so you offer a game to share the coins to ...
8
votes
3answers
354 views
Four-in-a-line Puzzle
Disclaimer: This is an open-problem, I don't have a complete solution for this puzzle yet.
We are playing a $2$-player game: you as a challenger and me as a judge. Initially, there is an empty ...
37
votes
2answers
4k views
Pirate democracy at its finest
With our pirate crew becoming too big, the captain grew very concerned about splitting all the treasure - we continued to split it equally, but, of course, each crew member got less and less with the ...
13
votes
3answers
2k views
99 coins into the sacks
You have 99 coins that you need to place into any number of sacks. After doing so, you write on each one the number of sacks that are lighter than that sack. For example, if you put 98 coins into one ...
5
votes
7answers
651 views
The selling of the sheep [closed]
I do not know the answer to this puzzle, and I found it in some old files I had
Many years ago, there was a shepherd with 3 children. One day, while talking to the owner of the herd, the shepherd ...
6
votes
1answer
243 views
Dividing the gold
There is a king and 3 women in a castle. One day, the king give 3 women a total of 100 golds. He said that each woman can propose an idea to share the gold among themselves. If the proposal passed ...
4
votes
2answers
273 views
100 prisoners' names in boxes, against smart warden
My question, which I do not know the answer to, concerns the classic 100 prisoners and 100 boxes puzzle, summarized below. The solution to this assumes the names are placed in boxes randomly, and gets ...
30
votes
8answers
2k views
Wolves and sheep
All the sheep were living peacefully in the Land of Shewo. But suddenly they were struck by a danger. A few wolves dressed up as sheep entered the territory of Shewo and started killing the sheep one ...
17
votes
5answers
869 views
Blindfold Bingo
Congratulations, you have been selected from among the audience to compete in the fabulous Blindfold Bingo challenge! (cue annoying, yet catchy theme music.)
Here you see our perfectly ordinary Bingo ...
6
votes
2answers
265 views
“Balls in Boxes in a Sack” Weighing Problem
This puzzle is based on a competitive programming problem in SG NOI 2019.
Let's assume there are $100$ balls with some labels (e.g. with $100$ different marks on them) having different weights of ...
7
votes
3answers
406 views
Writing differences on a blackboard
The numbers 25 and 36 are written on a blackboard. At each turn,
a player writes on the blackboard the (positive) difference between two numbers
already on the blackboard, if this number does not ...
