*Shrug*
With those, you might find a Highland and a Lowland on one and a full pack of Frenzied on the other.
The upper limit mob you could take would be dictated by how fast the mob can kill the Highland vs it being healed, vs the Mob being killed by the Pack of Frenzieds.
In all cases it is always a DPS vs Hit Points, in both directions.
Just in case, DPS= Damage Per Second.
The mitigating factor on both sides, is the Effective Hit Point Regen. This is Natural+External Heals (Direct Heal and Heal over time).
Assuming you do not lose health points or your proxy (the pets) the amount of time the encounter takes is directly related to the DPS vs Health Points + Health Point Regeneration Rate.
Or more generalized Duration in Seconds=HitPoints / (DPS-HRRS), where again, HRRS = Hit Point Regeneration Rate in one second. DPS = Sustained Damage Per Second (Burst Damage per Second can be added to this, meaning damage spells etc. but is a bit more variable and therefore a bit more complicated unless you take readings over long periods of time and derive a more or less accurate average) In case some one wants to argue about Disco'd mobs then keep in mind it doesn't really change the formula it simply increases or decreases (depending on which side your looking from) the DPS.
/Begin Sarcasm
The above spread sheet playing of a MMORPG is due 100% to the knowing the numbers that go into the formula.
/End Sarcasm
If we did NOT know them, then we would be required to rely far more on the Player of the Characters Skills.