If you have other interactive objects such as click boxes or buttons in your sims set to report to quiz then each of these will also be counted as a question.
Go to Project > Advanced Interaction and check the dialog to find all scored objects in the project. Then if you do not want those objects included in the quiz scoring, go to the slides containing the objects, select them, and in the Properties tab > Reporting accordion deselect the option to Include in Quiz.
