echo date('H:i',$total).' + '.$telat2.' = ';
$total = $total + strtotime($telat2);
echo date('H:i',$total).' ';
<?php
$time1 = '00:00';
$time2 = '00:35';
$time1_unix = strtotime(date('Y-m-d').' '.$time1.':00');
$time2_unix = strtotime(date('Y-m-d').' '.$time2.':00');
$begin_day_unix = strtotime(date('Y-m-d').' 00:00:00');
$jumlah_time = date('H:i', ($time1_unix + ($time2_unix - $begin_day_unix)));
echo $jumlah_time;
?>