There are two ambiguous terms there,
Voted on 600 questions and 25% or more of total votes are on questions
questions refers to questions and their answers; so in practice, voting for this answer would count, and voting for the question would count, but voting for both the question and the answer would only count once.
This then makes the
total votes clearer, as this badge is going to count all things reported as up and down votes on your profile (comment up votes are not, at present, nor do they count) - you need 25% of all those votes to actually be on the question and not the answer (actually, voting for both question and an answer will count for the first total, and move your weighting toward 50%)