You suggested (successfully) that to display both pages and posts in the slider to change code to:
$additional_loop = new WP_Query(array('post_type' => array( 'post', 'page' ), 'posts_per_page' => 5, 'post__in' => array(37,50,54,30,32)));
That works great! Thank you.
However, can you change the code so that the order is reversed from where it is now. Pages, then posts and not posts then pages? What would be the new code?