If the pass mark for your overall module is 40%, then you would need to get a minimum of 49% in your presentation to be able to JUST pass the module as a whole (if you got 49% in the pres then your overall mod mark would be 40.2%). If you want to know the exact maths of how I worked that out let me know.
Long story short, you can still pass the module, just work hard on your presentation and you'll manage it. Good luck!