My math may be wrong, but from what I understand...
You said you got 9.2% of a possible 20% on the test portion, and 16.8% of a possible 30% (I'm assuming that's what you meant based on the way they display the marks on elm).
So you have 26/50 currently, meaning you need to get 24/50 to pass the class. ie, 48% on the exam. Ivan was basically right the first time, but you need to get 24% of the possible 50%, not a 24% mark.
If it helps, you can think of it as only needing to get 48 questions right, since the exam is out of 100. It might also help to realize you aren't actually failing right now, you have a mark of 52%. So as long as you pass the exam, no worries.
This is assuming that your "Grades" page says you have 16.8/30 for your final lab mark, and that your two test marks out of 10 sum to 9.2. If you have different values, then I misunderstood you.
Again, aiming above that mark doesn't hurt though