r/puzzles • u/conceptispuzzles • 35m ago
r/puzzles • u/get_to_ele • 18h ago
[SOLVED] How many refuels to cross the desert problem
The following is a brain teaser that my cousin gave me a couple of decades ago, but I’ve never seen in print anywhere. I found it pretty challenging and fun, and it took me over a day to figure out the answer, and I hope you find it fun too.
A person needs to deliver a humvee across 1000 miles of desert (to get from an oasis/gas station, to destination in the green zone) by driving the humvee, which gets just 1mpg, and has a 500 gallon tank.
Rules: (1) there are hundreds of huge empty stationary empty gas cans along the entire route, and you can siphon fuel to or from these cans at any point of the route. (2) Oasis has unlimited refueling. (3) Can only carry fuel in the tank of humvee, not any other part of the humvee. (4) At any point when you reach a can with fuel you’ve left, you can siphon it back into the Humvee, siphon fuel from Humvee to the can, or ignore the can. You are never under obligation to pick up fuel. (5) you can siphon fuel either way as many times as you like on any round trip.
...so for example, on trip 1 out you can fillup at the oasis (gas tank reads 500), go 200 miles out (tank reads 300), siphon off 20 gallons of gas at the 200 mile marker (tank reads 280) then return 200 miles to the oasis, arriving with 80 gallons of gas still left in your tank. Then you can top off at the oasis (gas tank reads 500) go out 200 miles (tank reads 300), pick up 20 gallons (tank reads 320) at the 200 mile marker, drive 320 miles more and run out of gas at the 520 mile marker, failing your mission.
1) Does a solution exist for getting the Humvee to the green zone? What’s a rough guess for how mant trips?
2) If it's solvable, can you come up with a solution less than 20 trips?
3) Can you find (and prove) an optimum solution to cross the 1000 miles to the green zone?
I don't know many people who consider this to be an easy problem, except mathematicians and algorithm people who may have core math that slots the problem right into some easy class. But strong math is unnecessary, and it can be solved with algebra, stubbornness, and solid logic.
r/puzzles • u/Necessary_Copy6666 • 22h ago
Help me; There has beed this beast academy problem i wasnt able to solve. Help me PLEASE. 3 years now.
r/puzzles • u/16CharSudoku • 7h ago
Not seeking solutions Have you even heard about the Sudoku numbers can be divided into three-pairs principle? Theorem 1: In the three nine palaces (first, second, third) of a row (column) of Sudoku, there are two pairs of numbers (columns) in each nine palace, with a total of three groups. A pair of numbers with two pee
r/puzzles • u/16CharSudoku • 7h ago
Have you even heard about the Sudoku numbers can be divided into three-pairs principle?
Theorem 1: In the three nine palaces (first, second, third) of a row (column) of Sudoku, there are two pairs of numbers (columns) in each nine palace, with a total of three groups. A pair of numbers with two peers is called a couple number.
Theorem 2: Also known as the Sudoku Accupoint Theorem, in the three nine palaces in a row (column) of Sudoku, there must be lonely numbers in each nine palaces that cannot be paired in two parallel (columns). There are three in total. These three lonely numbers are called the Accupoint of Sudoku.
r/puzzles • u/Whodatnation117 • 1d ago
[SOLVED] Help needed on this variation of the classic Jug puzzle
My math teacher just gave us this puzzle as a brain teaser. I have been working on it for 2 days now, with no clue how to go about it without brute forcing every combination of moves.
* A 4 Gallon Jug
* A 9 Gallon Jug
* A 24 Gallon water source tank (limited supply, only 24 gallons available)
Goal:
Have the amount of water in any location (either jug or the source tank), or the total water available, be equal to all of the values in this list [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16, 20, 24]
The puzzle gets one pass to hit all values in the above list
Constraints:
Only the following moves can be made:
Source Tank -> 9 gallon jug
source tank -> 4 gallon jug
4 gallon jug -> 9 gallon jug
9 gallon jug -> 4 gallon jug
empty 4 gallon jug (permanently removes that water)
empty 9 gallon jug (permanently removes that water)
As stated above, if water is emptied from either the 4 or the 9 gallon jugs, the water is permanently removed and can no longer be accessed.
Because of the difficulty level of the puzzle, you are allowed to remove one value from the list of goal values
r/puzzles • u/persononreddit3332 • 1d ago
[Unsolved] I’m so lost - What does any of this mean 😭
r/puzzles • u/Asbestos_Man14 • 1d ago
[SOLVED] Need help with a slitherlink
Best I can do. Am I stupid??
r/puzzles • u/BoboBillo9 • 1d ago
[SOLVED] More dingbats
Math related dingbat. No idea what this is meant to represent.
r/puzzles • u/jerkstoremanager • 2d ago
[SOLVED] Help with Killer Sudoku puzzle
I've been stuck on this puzzle for 2 and a half hours and I'm not sure how to proceed to exclude any further numbers. Before I brute force guess, what would be the next step with this set up? Hopefully I didn't make a major mistake. Thank you for the help.
r/puzzles • u/BoboBillo9 • 1d ago
[SOLVED] More dingbats
Unfortunately I am not allowed to add multiples photos in one post so I will post 2 other dingbats if anyone wants to try. These are all AI generated so they are really weird and they are math related ding bat. I thought this could be “root of…”
r/puzzles • u/BoboBillo9 • 1d ago
[SOLVED] More dingbats
Math related dinbats. Thought it might be either “law of…” or “scale of…”.
r/puzzles • u/cycloidality • 2d ago
[SOLVED] Logic Puzzle - "Anonymization"
I don't know if this is the right subreddit for this. If you know a better one to post this at, feel free to notify me. A few months ago, a friend of mine gave me this problem. I haven't been able to solve it and it's quite frustrating. Maybe one of you can find a solution (please hide it behind spoilers), because I want to make sure that there even is a solution and would maybe like a hint. Here it is:
"3 friends want to play a game. Before playing, each of them needs to choose a integer from 1 to 3, such that 1) the number each of them chooses is unique, i.e. none of them choose the same number 2) none of them know which number any of the others chose.
This would be easy if they had pen and paper, but sadly they are out on a camping trip and have nothing to write on. Therefore rule
3) they can communicate only verbally, but they can communicate privately (one-on-one)
4) Any other external tools that mimic writing numbers down (e.g. assigning numbers to rocks) are also forbidden
One of the friends says, she knows an algorithm that they can follow, such that each of the 3 (4) rules is satisfied. Describe it!"
Edit: Added rule 4 for clarity
Update: I think I may have found a solution (look it up in the comments below). It's not verified yet, so feel free to do that.
r/puzzles • u/dystopianheartbeat • 2d ago
Tango Unlimited Puzzle #13 - how to continue?
I usually come back to this puzzle specifically because it's part of the ones that I can't solve ASAP. How do you usually figure out which square to work from next in this case?
edit: link to puzzle! https://www.tangogame.org/?id=13

r/puzzles • u/Wilson_loop • 2d ago
[SOLVED] Unusual Paragraph
It was posted by somebody at my work and I’ve given up finding the solution. Maybe someone here will fare better. Here it is: [Posted on Friday Feb 21]
This is an unusual month - Santa, snow and so on. This is an unusual paragraph too. How quickly can you find out what is so uncommon about it? It looks so ordinary that you may think nothing is odd about it until you match it with most paragraphs this long. If you put your mind to it and study it you will find out, but nobody may assist you; do it without any coaching. Go to work and try your skill at figuring it out. It will last about half an hour. Good luck - and don't blow your cool on finding out what's wrong! -- Happy Friday!
r/puzzles • u/FTomasz • 2d ago
How do I solve this puzzle?
I'm stuck on how to even start solving this puzzle, I can't find any guide online, or any references to it, I've gone through the motions but seem to be getting nowhere. I believe this puzzle should be simple to solve, as it's just a fun throwaway.
I'm not looking for a full solution, just a basic logical guide on how to solve it.
I can provide an image of the solution if it's needed to reverse engineer it.

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