<?php

/**
 * Limit numbers of questions to display in base page.
 *
 * @param array $args WP_Query arguments.
 * @return array
 */
function my_limit_questions( $args ) {
  $args['posts_per_page'] = 3;
  return $args;
}

add_filter( 'ap_main_questions_args', 'my_limit_questions' );