How to remove ?post_type=question from url

hello dstZloi,
I am also looking for the solution of removing the ‘?post_type=question’ from url. Please do reply.

I found the solution but it creates pagination problem.
Here the solution
$args = array(
‘posts_per_page’ => ”,
‘cat’ => $cat,
‘post_type’ => array( ‘post’, ‘page’, ‘custom_posttype’)
);
query_posts($args);