[Westbrook]

I think (is -4/5 an answer?

Yes, that's the correct answer for the problem as stated.

However, I think they meant to express it this way:

5q - 7p = 3

...which would have yielded a more rational answer of 2.

[AnAmericanMother]

That's exactly why I was doubtful . . . the other two math problems yielded nice, round, non-negative numbers.

Multiple choice problems generally have fairly straightforward choices (except when you draw a really bad section on the SAT maths, or the Math ACT, then all bets are off.)