The article in this week’s *That’s Maths* column in the* Irish Times* ( TM038 ) is about Rubik’s Cube and the Group Theory that underlies its solution.

## Posts Tagged 'Puzzles'

### Speed Cubing & Group Theory

Published February 13, 2014 Irish Times Leave a CommentTags: Algebra, Algorithms, Group Theory, Puzzles

### The Watermelon Puzzle

Published November 14, 2013 Occasional Leave a CommentTags: Algebra, Puzzles, Recreational Maths

An amusing puzzle appears in a recent book by John A. Adam (2013). The answer is very surprising. The book argues in terms of simultaneous equations. A simpler argument, using the diagram below, should make all clear. Continue reading ‘The Watermelon Puzzle’

### Chess Harmony

Published January 30, 2013 Occasional Leave a CommentTags: Games, Number Theory, Puzzles, Recreational Maths

Long ago in the Gupta Empire, a great-but-greedy mathematician, Grababundel, presented to the Maharaja a new game that he had devised, called Chaturanga.

Thirty-two of the Maharaja’s subjects, sixteen dressed in white and sixteen in black, were assembled on a field divided into 64 squares. There were rajas and ranis, mahouts and magi, fortiers and foot-soldiers. Continue reading ‘Chess Harmony’

### Sharing a Pint

Published December 13, 2012 Occasional Leave a CommentTags: Analysis, Archimedes, Puzzles

Four friends, exhausted after a long hike, stagger into a pub to slake their thirst. But, pooling their funds, they have enough money for only one pint.

*Annie* drinks first, until the surface of the beer is half way down the side (Fig. 1(A)). Then *Barry* drinks until the surface touches the bottom corner (Fig. 1(B)). *Cathy* then takes a sup, leaving the level as in Fig. 1(C), with the surface through the centre of the bottom. Finally, *Danny* empties the glass.

**Question**: Do all four friends drink the same amount? If not, who gets most and who gets least? Continue reading ‘Sharing a Pint’