By default, your quiz will be assigned a maximum grade of 10, regardless of the number of questions you have added, or their weighting. You can edit the maximum grade of the quiz, and the maximum mark for each question, via the ‘Editing quiz: [quiz name]’ page. This page can be found by clicking on Quiz > Quiz administration (from within the Administration block) > Edit quiz.
You will need to ensure the total grade of your quiz questions (combined) is equal to the maximum grade of your question (in total). For example, a quiz with two questions which each have a ‘maximum mark’ of 5, can have a maximum grade of 10.
To edit the maximum mark of your quiz questions, click on the pencil icon to the right of your quiz question on the ‘Editing quiz’ page. Hit enter once you have changed the maximum grade.