You can remove a quiz from a collection as easily as adding one to a collection. Please follow the steps below to know how to go about removing a quiz.
Step 1: Access your collections by clicking on the 'Collections' tab.
Step 2: Click on the collection from which you want to remove quiz.
Step 3: Click on the Remove button to remove the quiz from your collection.
On clicking the remove button, the quiz gets deleted as shown in the image above (Quiz titled "Mathematics" is removed).