Applying for jobs with a slash as a grad teacher

e.g. English/Humanities

Is it safe to assume that the first one is the main, the next one is the side

e.g. They're expecting 60% English, 40% Humanities?

Should I apply if one of the slashes is not my method

I am keen to teach but I have never had experience, not even as a PST

Is there a possibility of negotiating so that you take on only one of the slashes, albeit with a lower FTE?