I didnt have a clue where to put this so forgive me!

I didnt hand in a piece of work worth 20% of a subject i am taking. There are two other pieces of work, one worth 30% and the other worth 50%. So i still have 80% of the marks out of the whole subject to attain.

What % do i have to score in each element to pass, given that 40% is the average mark i need for the whole module?

Thanks