How to change the quiz timing
First, log in to your CDX account and navigate to the desired course. On the course page, click the chapter that contains the quiz. In the top right corner of the chapter page, click the Actions button, then click Turn editing on.
Click the Edit option next to the quiz you want to edit, then click Edit Settings. On the settings page for the quiz, click Timing. Then, complete or edit the fields to set a start or end date and time or set a time limit for the quiz. You must leave the Enable checkbox ticked to apply the changes.
Once you’ve finished, click Save and return to course to save your changes or Save and display to view the quiz or make additional changes to it.