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I'm not sure if this will work as you need, as far as I know you can not create your "database" of questions and answers and only use them on different forms.
However, we have an app that will help you to create a test/quiz form, here is the link to the app: http://apps.jotform.com/app/quiz_form.
Here is a guide that will help you to turn your form into a quiz: http://www.jotform.com/help/289-Turn-your-form-into-a-Quiz-or-Exam-.
Hope this will help you.