Thank you very much to everyone who submitted an entry to Competition S2, based on Professor Alan Grafen’s article on The Mathematics of Natural Selection. Given the nature of maths, it’s easy to make a minor mistake and miss out on a perfect answer; each submission was given our full consideration, and evaluated based on the overall quality of the entries and on the ways in which problems were approached, even where mistakes were made. We’ve uploaded our example answers for you to see how we tackled the questions and to compare your solutions to! Below you can read some of the winning entries, as selected by our team of markers.