Will be interesting to see the answers of other instructors, @MilanYadav , but there were a few posts around this in the past and I'd say 20 - 30% is the average number.
I've got several courses on UfB myself and in my case it's between 20 and 40%, and rather increasing towards the 40% mark.
The UfB revenue will be paid out together with your platform sales of the respective month. There is no separate payment.
Does this answer your question?
