If your midterm marks are less than stellar, there is still hope.
When I mark the final, I will identify the questions corresponding to each midterm, and I will assign them a "midterm mark within the final". For instance, say the first 4 questions in the final correspond to the topics in midterm 1. Then I will calculate a grade from those 4 questions; if that grade is better than your midterm grade, then it becomes your midterm grade. And, of course, a similar process will occur with the second midterm.
In summary, you can still get 100% in both midterms. The trick is to be ready for final!