Please help me formulate interview questions. I will be interviewing a college grad and a professional?

Our final project in math will be interviewing a professional and a college graduate majoring in the course that we will take (in this case, I will be interviewing a college grad and a professional who majored in comsci). I've already made one but it seems that I've ran out of ideas of what to ask next. The interview should last for like 3-5 minutes and a lot of back-up questions will be a great help (I might interview a person who answers really short). I only managed to create 5 questions for each. I also find it difficult on how I should plan the questions for the professional. Also, it would be really nice if you could help me put more umph (?) of this question I had...it's about what mathematical concepts we could find in computer science? I want to compare and contrast the point of view of the professional and the college grad regarding this. Please help me formulate interview questions for both the college grad and professional. I've never done interviewing before, so please help me. I'd be truly grateful.