Math Guru's- please help

[Tsunami]

Man talk about Murphy's Law...

Took 2 finals today, thought I aced my Bio test, but came out with a B, but my overall avg for that class with the B is 98% so I should still have an A.

So just finished taking my Medical Terminology class online just past midnight and before tonight I never had problems with taking my tests online. Of course tonight the server started freezing and didn't take some of my answers. So I emailed the professor and I am waiting until tomorrow to see if I can or should retake the test. The final is just 25% of my grade though so I am trying to figure out how badly I have to score to maintain my A. But my math sucks ass and I just can't figure it out. (Plus I'm braindead right now, its 3:30 am)

Here is the breakdown:

20% of my grade I have 100 avg
30% of my grade I have 98
25% of my grade I have 97.2
25% of my final- TBD

How low do I have to score on the final to average out a 93%?

Thanks!