Guild Wars 2

First, I know that this question is valid for all professions, but might is very easy to get as a warrior.

So, if I have 2 superior runes of strength and 2 superior runes of fire (they both give 20% increased might duration), what would the end result be?

+40% might duration

Or

You can just unequip them, test the length.

Equip them, test the length.

It does stack so I can have the stacks of might from signet of rage last the entire cool down