Intelligence vs. Work Ethic

Yesterday during my investment banking interview I was asked to rate myself on a scale of 1 to 10, 1 being intelligence and 10 being work ethic. How do you answer a question like that?

Here's my response and rationale. I rated myself "6 or 7" because I thought my GPA and part-time economics job demonstrated intelligence; thus I put more emphasis on my work ethic, which would be more difficult for an interviewer to identify. I also (politely) said that the question was misleading because in most results-oriented environments, intelligence and work ethic are complimentary, rather than opposites.

Where would you rate yourself?