Quiz: Fix division by zero + fix e_notice

main/exercise/answer.class.php

@@ -849,7 +849,7 @@ class Answer
 
         if (count($this->position) > $this->new_nbrAnswers) {
             $i = $this->new_nbrAnswers + 1;
-            while ($this->position[$i]) {
+            while (isset($this->position[$i])) {
                 $position = $this->position[$i];
                 $sql = "DELETE FROM $answerTable
                         WHERE

main/inc/lib/exercise.lib.php

@@ -5176,8 +5176,8 @@ EOT;
                     continue;
                 }
 
-                $total_score += $result['score'];
-                $total_weight += $result['weight'];
+                $total_score += (float) $result['score'];
+                $total_weight += (float) $result['weight'];
 
                 $question_list_answers[] = [
                     'question' => $result['open_question'],

plugin/xapi/src/ToolExperience/Statement/QuizQuestionAnswered.php

@@ -53,7 +53,7 @@ class QuizQuestionAnswered extends BaseStatement
 
         $rawResult = $this->attempt->getMarks();
         $maxResult = $this->question->getPonderation();
-        $scaledResult = $rawResult / $maxResult;
+        $scaledResult = $maxResult ? ($rawResult / $maxResult) : 0;
 
         $context = $this->generateContext();
         $contextActivities = $context