Well, if anyone was wondering....
The known scores I have for my test were 72, 73, and 69%
Based on that the only combination that can exist is they threw out exactly 2 questions:
57/78 = 73.07% rounds to 73%
56/78 = 71.7% rounds to 72%
54/78 = 69.23% rounds to 69%
78 total questions is...