These code-breaking puzzles are from MathsJam Shout for October 2025. The second one is reminiscent of the mesmerizing 1970s game Mastermind, which consumed many hours of my time.
See Two Codebreaking Puzzles for solutions.
Tag Archives: MathsJam
The King of the Spiders
Continuing the logic thread, this is a nice logic problem from MathsJam Shout for April 2025.
“The king of the spiders has four servants, and the servants have either 6, 7, or 8 legs. Servants with 7 legs always lie, and servants with 6 or 8 legs always tell the truth.
The king asks ‘How many legs do you four have in total?’, and the four spider servants (who are standing behind a table, so you can’t see their legs) answer 25, 26, 27, and 28, respectively.
Who is telling the truth?”
See The King of the Spiders for a solution.
Mystery Number Puzzle
This is a slightly different mystery number puzzle from the December 2023 MathsJam Shout. It provides a simpler puzzle as a respite from the more challenging problems.
Point of Intersection Problem
I came across an interesting problem in the MathsJam Shout for February 2022.
(“MathsJam is a monthly opportunity for like-minded self-confessed maths enthusiasts to get together in a pub and share stuff they like. Puzzles, games, problems, or just anything they think is cool or interesting. Monthly MathsJam nights happen in over 70 locations around the world, on the second-to-last Tuesday of each month. To find your nearest MathsJam, visit the website at www.mathsjam.com.”)
“Given two lines Ax + By + C = 0 and ax + by + c = 0, is there a simple link between the vectors (A, B, C), (a, b, c), and the point where the lines cross?”
The answer, of course, is yes, but the question is somewhat open-ended and I was not able to track down any answer given.
See the Point of Intersection Problem