That entirely depends on your damage type vs. their resistance profile (which is greatly different between the burners). A Nergal with the right setup can kill all of them, some sooner, some later. Other ships rely on hitting the Burner’s weakest resistance. Assaultfrigs/Factionfrigs usually deliver enough DPS to do it, if you survive long enough. So, assume 250 DPS if you can hit their resistance hole, ~400+ if you can’t and just need to overwhelm them with raw damage.
If you want to run the pirate burner missions efficiently, fit one Counter-Frig per Burner Opponent, specialized for killing exactly this one. Its usually faster to just switch ships than to refit one ship.