models/classes/runner/time/QtiTimer.php
public function getExtraTime($maxTime = 0)
    {
        if ($maxTime && $this->getExtendedTime()) {
            $secondsNew = $maxTime * $this->getExtendedTime();
            $extraTime = $secondsNew - $maxTime;
            $this->setExtraTime($extraTime);
            return $extraTime;
        }
        return $this->extraTime;
    }
public function getExtraTime($maxTime = 0)
    {
        if ($maxTime && $this->getExtendedTime()) {
            $secondsNew = $maxTime * $this->getExtendedTime();
            $extraTime = $secondsNew - $maxTime;
            $this->setExtraTime($extraTime);
            return $extraTime;
        }
        return $this->extraTime;
    }
Gets the added extra time
@param int $maxTime
@return float