Using query_post ()

I’m placing a selection of 3 blog posts on a simple page, and want only those posts from category 15 or 16. I’m able to select category 15 or 16 by itself, but not together.

I’ve tried category_in and category_and and various other combinations but no luck. If I don’t select just one category, then all categories show on the page.

This should be simple, but no matter what I try it won’t work. Thanks in advance.

‘<?php
$paged = (get_query_var(‘paged’)) ? get_query_var(‘paged’) : 1;
$args = array(
‘category_and’ => array(15,16),
‘posts_per_page’ => 3,
‘paged’ => $paged );
query_posts($args); ?>’

The Loop and reset