<?php
 
$tarr = array('2:10', '3:15','6:59','2:22');
echo sum_the_time($tarr);  
 
function sum_the_time($times) {
 // $times = array($time1, $time2);
  $seconds = 0;
  foreach ($times as $time)
  {
    list($hour,$minute) = explode(':', $time);
    $seconds += $hour*3600;
    $seconds += $minute*60;
  //  $seconds += $second;
  }
  $hours = floor($seconds/3600);
  $seconds -= $hours*3600;
  $minutes  = floor($seconds/60);
  $seconds -= $minutes*60;
  // return "{$hours}:{$minutes}:{$seconds}";
  return sprintf('%02d:%02d:%02d', $hours, $minutes, $seconds); 
}
 
?>

14:46:00