Please tell us everything you know about this test. Since "logarithmic scoring" doesn't seem to be defined, at this point we know nothing about how it is scored.
It sounds like you may be talking about an adaptive test, which effectively skips over questions you are expected to get right, in order to more quickly get to the questions that will narrow down your ability. As a result, the number of questions you get correct is unrelated to your score. Rather, it depends on which questions you answer.