Puzzle Definition and 595 Threads

This is from the front cover of Mathematical Conundrums, CRC Press, 2023. << When Holly was twice the age Ivy was 15 years ago, Ivy was half the age Holly will be in 12 years time. How many years ago was that? >> OK, but why isn't the age of Holly and Ivy given?

TL;DR Summary: This should be a simple maths problem Can anyone solve this as I can't. I found it in my son's school book which we cannot do. (see picture attached).

A Japanese woman living in Spain miraculously emerges unscathed from an automobile accident. To show her gratitude she adopts a cat and names it Aristotle. Why is that?

Here is my attempt. Beginning state: Bag B : B, B, O Bag A : R, R, G, V, Y Final state: Bag B: B, B, O, + G/V/Y Bag A: remaining balls First possible exchange that would have exactly 3 different colors in each bag is: Move 1: P ( Arjun moves either the green, violet, or yellow ball to...

Could you please help me understand why the answer picture says the length of the two sides of the triangle are 1.33 yard each? Thanks

Hello! I’m an assistant of a mathematical scientific researcher, and my research programme evolves around finding and developing all the (possible) solutions regarding all unsolved mathematical, logic, exact, and IQ puzzles ever created. If you search on the internet for: “The hardest unsolved...

Any clue what this would be?

Dear everyone, I wish to discuss in this thread a classic/semi-classic interpretation on the origin of Bekenstein-Hawking entropy and the related resolution to Hawking's information missing puzzle, which were published in Nucl.Phys.B977 (2022) 115722 and Nucl.Phys.B990 (2023) 116171 after...

Hmmm, , Does gravitational time dilation (speed up) cancel out earth orbit time dilation (slow down) for astronauts, , , it must do, to a certain extent Hmmm, , ,Mick's been thinking = the present is a continuous but fleeting moment, that allows the future to flow into the past, , ,so does the...

I'm 82 and was browsing through a old comic annual that was published back in the 1950's (Eagle Annual No 3). It had a puzzles page and one of the puzzles was quote: 'I have a pair of scales and 3 weights and with these 3 weights I can weigh any number of pounds from 1 up to 13.(I may, of...

There are 4 players numbered 1 to 4. There is a room with an entrance door to one side and exit door to opposite side. Inside the room, there are 4 boxes numbered 1 to 4. Inside each box, there is a chit containing a number (with equal probability) from 1 to 4 (inclusive). No two chits can have...

So, this problem is going to require some explaining.. I'm a Production Engineer who's recently started working at an adhesive tape converter/distributor and I've been working on an industrial rewinding machine for films, tapes, foams etc. The tapes I rewind range from 0.2mm - 3mm thickness...

A few days ago I was watching a youtube video of someone solving a jigsaw puzzle and a thought came to my head; is it possible to make a maze with only one entrance and only one exit that is printed out on a jigsaw puzzle, where the only way the maze is traversable is if the puzzle is solved in...

Hi everyone. I came across the following brainteaser: A plane travels from airport A to airport B and then returns to A from B. There is no wind, both trips follow a straight line, and the plane flies at constant engine speed. Suppose now that a constant wind is blowing from A to B. Will the...

So I am missing something in this one. The answr is 8. Can someone explain? In a department store, with only one girl working on the gift-wrapping service, four gifts per hour were wrapped in the first 15 hours. With help from a colleague for the next 45 hours, the amount of gifts wrapped rose...

I have been trying to find a pattern in this sequence of numbers: 72.1, 25.2, 35.1, 58.3, 164.14, 99.8, 23.1, 51.5, 13.2 I have tried every method I can think of like finding the mean, putting them in numerical order, trying to see if the differences between each number has any correlation (It...

My solution is However can someone explain in detail why will be equal to the weight? and why does it have to be multiplied by 6?

Ball X has mass 0.03kg. It falls vertically from rest from a window that is 30 m above the ground. Ball Y has mass 0.01kg. At the same time that Ball X starts to fall, Ball Y is projected vertically upwards from ground level directly towards Ball X. The initial speed of Ball Y is 20 m/s...

can anyone help solve this puzzle regarding regular expressions? I was given this in an interview test from BAE systems cyber security department a few years ago and just came across it again, still haven't managed to get anywhere like an answer. I have tried matching each line of regex to form...

I know that the puzzle is related to the LCM of the denominators of the fractions. I could create a few of my own puzzles too (for example, 23 camels to be divided in 1/2, 1/3, 1/8th). But I have some more questions about this puzzle. 1. What is the formal name for this solution method? 2...

Just for fun (read as: staring at the ceiling trying to sleep), trying to figure out if there is a programmatic way to solve this colour-matching puzzle app on my phone. It's called... Here is a partially solved puzzle: The dotted tiles are immovable, and serve as references. The undotted...

I mentioned in another thread that I've been playing with a C++ class for 3D vectors, to review overloaded operators, constructors, etc. All those functions display output so I can follow which ones get called, and when. The class generates a serial number for each vector so I can tell them...

After trying a few combinations of a1 and d, I looked up the answer and the anwer was: 482, 3362, 6242, where d is 2880. After seeing such a complicated answer a few questions popped into my head: 1. Could someone have actually manually worked this puzzle out or did the author just ran a...

There is a precise sense in which it is correct to say: $$\sqrt {car}=37$$ The puzzle is to figure out in what sense this is true. [What made this so exciting for her is that 37 is her favorite number, and that she was obsessed with car models at the time].

I was finding the energy required to separate tritium into it's component parts, the binding energy when it hit me that how could 1amu= 931.2 MeV and 1.66e-27 kg at the same time?

Of all the possible four digit numbers how many are the produce of two two digit numbers? Can the process be easily generalized to other combinations? Thanks.

I am at my wits end with trying to find this formula. So far all I've gotten is I need to figure out mechanical power, maybe torque? I can't figure out the formula for this motion as it is like negative leverage. I want to build a machine that can do this thousands of times so I also need to...

"Collection of Problems of Mechanics" by Meshcherskii.I see how the answer could be arrived at because each successive drag increases the number of ropes that must be used, but what I don't understand is why the thrust and drag of the tug doesn't play a role in the number of ropes required.

Hello! My homework is making a crossword. I write a code like this: do{ //code printf("Please enter the coordinate and the word: \n"); scanf(" %c%d %s",&row2,&column2,word2); if(row2=='E' && word2=="xit") exit(0); //code }while(count2!=10); But this is...

In the fig attached we have to find what will be the digit in the missing box i can't figure it out

Unfortunately, the only source I could find on the internet is the one I cited in the summary. This source has the date and GMT time for the two annual equinoxes and the two solstices for a hundred years: 2001-2100. The 99 time difference values, Ai, shown in the graph below were calculated as...

This is a puzzle involving the orbit of the Moon around the Earth, based on the well-known story of Newton observing a falling apple and wondering if the same force that made the apple fall could also explain the motion of the Moon. The story goes that Newton considered the following: the...

https://www.quantamagazine.org/how-pi-connects-colliding-blocks-to-a-quantum-search-algorithm-20200121/ and related papers: Play Pool with PI (2003 paper by Galperin) https://www.maths.tcd.ie/~lebed/Galperin. Playing pool with pi.pdf and Playing Pool with |ψ⟩: from Bouncing Billiards to...

Gallilean Invariance states that the laws of motion are the same in all inertial frames. One experiment involved being on a ship below deck with no frame of motion reference. Supposedly, there is no experiment which could show whether the ship is moving or in what direction or speed. I was...

A gear A has 50 teeth and another B has 10 teeth, how many times does the small gear rotate around the big one? I thought 5 but its 6! Note: The gear is curved like 360 degrees.

Summary: Advice on books for software engineer logic puzzles for interviews and improve overall skills I am looking to getting into software engineering, and am having trouble with find the logic puzzle books or websites to prep for interviews. Now of course there lots of logic puzzle type...

All basic laws of physics are said to respect CPT symmetry, and Maxwell's equations in particular are time-symmetric. But here's a simple scenario I find very puzzling: Two particles of opposite charge attract each other. In the time-reversed picture, they'd repel each other, no? But they...

Hi, please see attached image below. Do you know why the indicated outlet, out of everything in this mess of a circuit, has particularly high AC Magnetic EMF emanation? The wiring inside the outlet box looks normal and standard (2 neutrals on left, 2 hots on right, grounded correctly, no ground...

Puzzle: 5.2.7.7 | 3.2 | 7.2.4 | {7}.7.2 hint #1) Irrational hint #2) 2 to 101 Can anybody help me figure this out? There are 2 hints. I am at a loss.

Hi, This is not homework. I am struggling with a puzzle from this book (page 6, puzzle #13). I know the answer of the puzzle but I can't seem to figure out a good approach. 1. Homework Statement A man left legacies to his three sons and to a hospital, amounting in all to $1,320.00. If he had...

A while back I posted a black hole horizon puzzle. This is another puzzle in the same general spirit. It is based on the scenario described in this old PF thread: https://www.physicsforums.com/threads/a-flaw-of-general-relativity.115418/ Needless to say, as was the case with my previous...

Eight queens puzzle - Wikipedia -- place eight chess queens on a chessboard so that none of them attack each other. It turns out that there are 92 solutions, though when one counts together positions related by chessboard symmetries, there are only 12 solutions. This problem has been modified...

A logic puzzle I just found online: $$ 5+3+2 = 151022\\ 9+2+4 = 183652\\ 8+6+3 = 482466\\ 5+4+5 = 202541\\ 7+2+5 = ? $$ [/SPOILER] Edit: The answer to the problem is not 14. Please post how long did the problem take you to solve:wink:

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Hi, I was playing this game in which you start from any cells of a 3x3 or 5x5 square and draw a line that loops through every cell in the box. The line can go only through a vertical or horizontal side (not diagonally). When you start from certain cells (problem cells), you can't reach at...

Hey all, for a dictionary app I have to code I have to implement as crossword game as a side feature, unfortunately this is compulsory, I can't figure out a good way of finding words that intersect each other (esp words that intersect multiple others) without a hell of a lot of goto and while's...

This past June, research by Marco Micheli et al was published in Nature: https://www.nature.com/articles/s41586-018-0254-4/ The gist of this article is that 'Oumuamua, (aka 1L/2017 U1) 2017's interstellar asteroid, was not following a strictly gravitational path around the sun. There is...

Homework Statement I'm making a ball cyclotron (https://rimstar.org/science_electronics_projects/ball_cyclotron_electrostatic_accelerator.htm) for a school project. To generate enough voltage, I'm using a Van der Graaf-generator. The problem is that all the voltage, which I can measure...

5 matches arranged to show 2 = 6: || = \/| Move 1 match only such that both sides are equal...