Mathematics

Terror networks are comparable in their structure to hierarchical organization in companies and certain online social networks, say the authors of a paper outlining how a mathematical model to…

Two days ago I wrote a quick post to stimulate non-flat-EEG readers to consider an apparently trivial question, which in fact hid many subtleties. The general question I wanted to address was whether…

It isn’t Monday, but I’m puzzled every day of the week. Alice is puzzled too; she’s playing with a new tetrahedral die. Each face has a different positive integer on it, but the numbers are peculiar…

After the scramble to get out of jail, here are some questions about imprisoned shapes! In my last question, we came across parts of the so-called harmonic series 1/2 + 1/3 + 1/4 + 1/5 ... 1/n. Now…

The solution to the Jailer’s Revenge question is fairly lengthy, so I think it warrants a separate blog entry. Please refer to the original question as it too is fairly long. Let’s firstly simplify…

A model based on global population data spanning the years from 1900 to 2010 has caused a research team to predict the opposite of what Doomsday Prophets of the 1960s and beyond insisted would happen…

This is a fairly new problem, being traced back to as recently as 2003. However, it also has the kind of counter-intuitive solution that has made it a favourite on mathematical websites and forums.…

The diagram below shows five concentric circles constructed in such a way that the area of each annulus is equal to that of the central circle. Within the first annulus, a square has been constructed…

Alice wants to play a game with Bill. She has just bought some new and rather strange dice. The average of each die is 3.5, just like a normal playing die, but the numbers on each face have an…

Let N be a non-zero natural number composed of n digits. Let us then both prepend and append the number 4 to create two new numbers, 4N and N4, that are both (n+1) digits long. For example, if N is…