php variables back and forth with xsl

[SaishuHane]

I want to be able to kind of have the php and the xsl work together so the random question and answer can be generated, but I'm really not sure how to do this. So far this is what I have in my php:

<?php
    $question_answer = array(
        1=>array(
            'question'=>'1+1',
            'answer'=>2,
            'text_answer' => 'two'
        ),
        2=>array(
            'question'=>'2+5',
            'answer'=>7,
            'text_answer' => 'seven'
        ),
        3=>array(
            'question'=>'3+1',
            'answer'=>4,
            'text_answer' => 'four'
        ),
    );

if($_POST['submit']){
    if ($_POST['answer'] == $question_answer[$_POST['question_answer_number']]['answer'] || $_POST['answer'] == $question_answer[$_POST['question_answer_number']]['text_answer']) {
            echo 'You got the answer right.';
    } else {
            echo 'You guessed wrong.';
    }
} else {

}
    ?>

And this is what I have in my xsl:

        <form method="post">
        Question:<?php $rand = rand(1,3); echo $question_answer[$rand]['question']; ?><br />
        <input type="hidden" value="<?php echo $rand; ?>" name="question_answer_number"/>
        <label for="answer">Answer:</label>
        <input name="answer" value="" /><br />
        <input type="submit" name="guess" value="Guess" />
        </form>

Many thanks for any help.