I'm not entirely sure I know precisely what you want. But maybe this info will help.
You can make a "formulas" type question that contains 10 sub-questions in it. When pulled up by your quiz, the student is presented with all 10 multiple choice questions, but it appears as 1 question in your data base. You could then treat this as a one "question set" of 10 sub questions. (As far as a model quiz is concerned is just 1 question).
Then you could make 100 of these formula type question. You then organize these in a questions in a folder in your question bank and design a quiz that selected some number question at random from the 100 'question sets'.
Set the quiz to give immediate feedback and I'd advise the setting that lets them "redo". Include a description question at the front of the quiz that instructs them that they have full credit when the reach 400 points. Those who want more practice can go ahead and do more. But others know they are done when they have 400 points.