Assuming there is no relevance/condition on the Multiple Numerical Input,
set up your survey to use JavaScript
and place the following script in the source of the question:
<script type="text/javascript" charset="utf-8">
$(document).ready(function() {
$('#question{QID}').hide();
setTimeout(function() {
('#question{QID}').fadeIn(300);
}, 30000);
});
</script>