Ask the interviewer. One of the things that I find most difficult about interviewing is when the candidate doesn't ask me any questions during the technical parts of an interview. If you aren't sure, you need to ask me -- I am perfectly capable of misphrasing a question or assuming you have context that you don't. Asking your coworkers for help is a perfectly legitimate problem solving strategy.

Interviewing is stressful and hard; no need to make it more stressful and harder on yourself.