Random Child Page

I’m trying to display a random child page’s content. Not sure how to go about it. So far I’m using the following code to display 2 child page’s content but I want these 2 to be random not the latest 2.

<?php
					$mypages = get_pages( array( 'child_of' => 48	, 'sort_column' => 'post_date', 'sort_order' => 'desc', ) );
					foreach( $mypages as $page ) {
						$content = $page->post_content;
						$content = apply_filters( 'the_content', $content );
						$count++;
					    if ( $count < 3 ) {  // only process 3 ?>
							<?php echo $content; ?>
					<?php
					}
				}
				?>

thanks