Edit $query statement to list 10 results

Hi,

I am trying to change the following code to list 10 posts:

$the_query = new WP_Query('showposts='. $posts .'&orderby=post_date&order=desc');
	while ($the_query->have_posts()) : $the_query->the_post();

I have tried the following without success:

$the_query = new WP_Query('showposts='. $posts .'&orderby=post_date&order=desc', 'posts_per_page = 10');
	while ($the_query->have_posts()) : $the_query->the_post();

$the_query = new WP_Query('showposts='. $posts .'&orderby=post_date&order=desc', 'posts_per_page' => 10);
	while ($the_query->have_posts()) : $the_query->the_post();

$the_query = new WP_Query('showposts='. $posts .'&orderby=post_date&order=desc', 'posts_per_page=10');
	while ($the_query->have_posts()) : $the_query->the_post();

The first one does nothing, the second and third list PHP errors on loading the site.

This code does list 10, but not in the way that I need:

$loop = new WP_Query( array( 'post_type' => 'post', 'posts_per_page' => 10 ) );
while ( $loop->have_posts() ) : $loop->the_post();

Should I use the original query as an array?