Question: What is the hardest mathematical problem you have ever soled and when?

Vincent Keenan answered on 14 Jun 2016:

That’s quite a tough question! Every problem is different and can often be solved in more than one way. The problem that has taken me the longest to solve has been working out a species invasion speed from some equations. It had taken me several months from calculating the speed, to checking it was indeed correct using big computers! All worth it in the end 🙂