What's the formula for the experience bonus after the colours of magic event?

Question

"Furb of Fun (orange): The shared experience bonus in party mode will be raised by 30%."

During duo hunt (ek/ed) Assuming, You are getting 30% shared party experience bonus, does it add another 30% of the bonus or it multiplies somehow the total exp (considering different stamina/boosts/preys)? 

For example, during normal hunts without it my duo made 3.4kk/h on average 100% exp gain rate stamina, with the event bonus we had 4.4k/h.

Answer 1

The tibia use the following to calculate the experience:

((Base 100%) + all calculated bonus in %) . 1.5 stamina

To focus in your question I will calculate without stamina bonus.

Example: a monster give you 1000 experience points at 100%, if you are in party(ED+EK)  its more 30%, so you have 1300 XP to share with your friend, that is, 650 for each.

During the event you will receive an additional 30%, so you will have 1600 XP to share, 800 for each.

In your example, you was doing 3.4kk/h without the event and with 100% (note here, that the % party does not appear on your skill's windows, so in fact this 3.4kkh already refers to 130%), with the event you receive more 30% and got 4.4kk/h.

https://tibia.fandom.com/wiki/Experience_Point