Complex sentence: Profits generated are shared between the parties according to a pre-agreed ratio--usually either 50% -50%, or 60% for the "mudarib" and 40% for "rabb-ul-mal".
Split into simpler sentences: Profits generated are shared between the parties according to a pre-agreed ratio. The profit is usually shared 50% -50% or 60% -40% for "rabb-ul-mal".