Adding two time using php

function sum_the_time($time1, $time2) {
      $times = array($time1, $time2);
      $seconds = 0;
      foreach ($times as $time)
      {
        list($hour,$minute,$second) = explode(':', $time);
        $seconds += $hour*3600;
        $seconds += $minute*60;
        $seconds += $second;
      }
      $hours = floor($seconds/3600);
      $seconds -= $hours*3600;
      $minutes  = floor($seconds/60);
      $seconds -= $minutes*60;
      if($seconds < 9)
      {
      $seconds = "0".$seconds;
      }
      if($minutes < 9)
      {
      $minutes = "0".$minutes;
      }
        if($hours < 9)
      {
      $hours = "0".$hours;
      }
      return "{$hours}:{$minutes}:{$seconds}";
    }