PHP Array and foreach Combination calculation - php

Question

In a quiz app, I am taking user answer using a form. I am retrieving correct answer from database table. I want to compare the correct answer with the user's answer and count how many answer was right and how many answer was wrong.
Here is my form:
<form id="question" class="" action="quiz_ans.php" method="post">
<table id="quiz-question" align="center" class="row-border compact order-column stripe">
<input class="form-control" type="hidden" name="NumberofQuestions" id="NumberofQuestions" value="<?php echo $NumberofQuestions; ?>">
<thead>
<?php
if($QuizQuestions) {
$i=1;
foreach($QuizQuestions as $row):
?>
<tr>
<th><?php echo $i; ?>. <?php echo $row->Question; ?>
<br>
<?php if(isset($row->Screenshot)) { ?>
<img src="<?php echo htmlspecialchars($row->Screenshot); ?>" alt="test" height="300" width="980">
<?php } ?>
</th>
</tr>
</thead>
<tbody>
<?php if(isset($row->Option1)) { ?>
<tr class="info">
<td><input type="radio" name="AnswerId[<?php echo $row->Id; ?>]" value="0"><?php echo $row->Option1; ?></td>
</tr>
<?php } ?>
<?php if(isset($row->Option2)) { ?>
<tr class="info">
<td><input type="radio" name="AnswerId[<?php echo $row->Id; ?>]" value="1"> <?php echo $row->Option2; ?></td>
</tr>
<?php } ?>
<?php if(isset($row->Option3)) { ?>
<tr>
<td><input type="radio" name="AnswerId[<?php echo $row->Id; ?>]" value="2"> <?php echo $row->Option3; ?></td>
</tr>
<?php } ?>
<?php if(isset($row->Option4)) { ?>
<tr>
<td><input type="radio" name="AnswerId[<?php echo $row->Id; ?>]" value="3"><?php echo $row->Option4; ?></td>
</tr>
<?php } ?>
<tr>
<td><label for="AnswerReason">Why?</label><input class="form-control" type="text" name="AnswerReason[]" id="AnswerReason" value=""></td>
</tr>
<?php if(isset($row->Id)) { ?>
<tr>
<td><input class="form-control" type="hidden" name="QuestionId[]" id="QuestionId" value="<?php echo $row->Id; ?>"></td>
</tr>
<?php } ?>
</tbody>
<?php
$i++;
endforeach;
}
?>
</table>
<br>
<input type="submit" name="submit" value="Submit" class="btn btn-success">
</form>
I am getting the user answer from the form submit:
$NumberofQuestions = $_POST['NumberofQuestions'];
$ans = implode("", $_POST['AnswerId']);
I am retreiving the correct answer from the database table:
try {
$sql = "CALL spQuizAnswers(:quiz_num)";
$stmt = $pdo->prepare($sql);
$stmt->bindParam(':quiz_num', $quiz_num, PDO::PARAM_STR, 50);
$stmt->execute();
$QuizAns=$stmt->fetchAll();
$stmt->closeCursor();
} catch (PDOException $e) {
die("Error occurred:" . $e->getMessage());
}
I am comparing the user's answer and the correct answer:
for ($i=0; $i<$NumberofQuestions; $i++) {
if($QuizAns) {
foreach($QuizAns as $row):
if($row->CorrectAns == $ans[$i]){
$right++;
} elseif($ans[$i] == 4){
$not_answered++;
} else {
$wrong++;
}
endforeach;
}
}
$CorrectAnswer = $right;
$WrongAnswer = $wrong;
$NotAnswered = $not_answered;
$TotalQuestion = $right+$wrong+$not_answered;
It does not give correct calculation. For 5 questions it gives $TotalQuestion=25.
How can I achieve the correct calculation? Any help would be much appreciated.