In my puzzle column earlier today I set you the following conundrum, concerning an incident in which six men were arrested during the 1605 Gunpowder Plot. Each of the men were questioned in private about who was a traitor and who was loyal. They made the following remarks.

Augustine: Felix is loyal, Erasmus is a traitor.

Bartholomew: Augustine is loyal.

Cuthbert: Felix is loyal, Bartholomew is a traitor.

Dionisius: Cuthbert is loyal, Bartholomew is a traitor.

Erasmus: Dionisius is a traitor.

Felix: Augustine is loyal.

It was known that loyalists tell the truth as far as they know it, so their comments about traitors can be trusted, but not their comments about loyalists. Traitors, on the other hand, know who is one of their own and who isn’t, and will always give false information.

How many traitors are there?

**Solution**

There are many ways to solve this puzzle, but the way I did it was to start by assuming that Augustine was loyal and see where it took me.

If Augustine is loyal, Erasmus is a traitor, which means Dionisius is loyal, which means Bartholomew is a traitor, which means Augustine is a traitor. We have contradicted ourselves, so we can assume Augustine is a traitor.

If Augustine is a traitor, Erasmus is loyal and Felix is a traitor. Which means Dionisius is a traitor, which means Bartholomew is loyal and Cuthbert a traitor.

So there are **four** traitors (A, C, D, F) and two loyalists (B and E).

I hope you enjoyed the puzzle I’ll be back in two weeks.

*I set a puzzle here every two weeks on a Monday. I’m always on the look-out for great puzzles. If you would like to suggest one, email me.*

*Todays puzzle is adapted from a question in the 2009 Australian Mathematics Competition, run by the brilliant Australian Mathematics Trust. It was written by Andrew Kepert.*

*I’m the author of several books of popular maths, including the puzzle books Can You Solve My Problems? and Puzzle Ninja.*