<?php
$mins = h2m(1.3);
echo date('Y-m-d H:i:s', strtotime("2016-04-01 15:00:00 + {$mins} minutes"));


function h2m($hours) {
            $t = EXPLODE(".", $hours);
            $h = $t[0];
            IF (ISSET($t[1])) {
                $m = $t[1];
            } ELSE {
                $m = "00";
            }
            $mm = ($h * 60) .  $m;
            return $mm;
    }
?>