public double calculateCommission()
	{
		this.commision = 0;
		this.commision = this.speaker.getRate() * this.duration;
		int dayOfWeek = this.getDayOfWeek(this.eventDate);
		if(dayOfWeek == Calendar.SATURDAY || dayOfWeek == Calendar.SUNDAY)
		{
			this.commision = this.commision * 1.25;
		}
		// add transportation fee of 500 kr
		this.commision += 500;
		return this.commision;		
	}