<?php
$time="01:07:37";
$mult=5;
$datetime=DateTime::createFromFormat('H:i:s',$time,new DateTimeZone('America/Sao_Paulo'));
$minute=$datetime->format('i');
$datetime->modify('+' . ($minute * $mult) . ' minutes');
$datetime->modify('-' . $minute . ' minutes');
echo $datetime->format('H:i:s');
PD9waHAKCiR0aW1lPSIwMTowNzozNyI7CiRtdWx0PTU7CiRkYXRldGltZT1EYXRlVGltZTo6Y3JlYXRlRnJvbUZvcm1hdCgnSDppOnMnLCR0aW1lLG5ldyBEYXRlVGltZVpvbmUoJ0FtZXJpY2EvU2FvX1BhdWxvJykpOwokbWludXRlPSRkYXRldGltZS0+Zm9ybWF0KCdpJyk7CiRkYXRldGltZS0+bW9kaWZ5KCcrJyAuICgkbWludXRlICogJG11bHQpIC4gJyBtaW51dGVzJyk7CiRkYXRldGltZS0+bW9kaWZ5KCctJyAuICRtaW51dGUgIC4gJyBtaW51dGVzJyk7CmVjaG8gJGRhdGV0aW1lLT5mb3JtYXQoJ0g6aTpzJyk7