If your instructor allows you take a quiz multiple times, then you can retake a quiz after submitting your answers as long as the due date and due time haven't passed. To find out whether your instructor is allowing multiple attempts, take the following steps.
Open the quiz from the LaunchPad home page
Click on the title of the quiz you want to open.
View the quiz policies
Look at the quiz policies to see whether you're allowed to take the quiz more than once.