Guild Wars 2

Mobs that stay longer alive in the world grant bonus exp.

My question is how long does it take for a mob to get to a point of giving out max amount of bonus exp?

from the time the mob spawns till the time it gives max amount of bonus exp,how long does it take?

Edit:

so after killing a far far away hidden mob it gave me 40 bonus exp.
i returned 10 mintes later and it gave me 10 bonus exp.

While i understand higher lvl mobs will grant me more, but if the bonus xp scales with time and level and amount… the result should be that it takes 40 minutes to take a mob to grant max amount of bonus kill exp

Hmm .. from my experience when farming yellow mobs in Dredgehaunt Cliffs
i would say maybe 20-30 minutes.