//: returns the cost per minute of a call to the argument zone;
	public double costPerMin(CallZone zone){
		double cost=0;
		if (zone.toString().equals("CANADA"))
			cost= 0.05;
		if (zone.toString().equals("USA"))
			cost= 0.10;
        if (zone.toString().equals("EUROPE"))
        	cost= 0.20;
        if (zone.toString().equals("ASIA"))
        	cost= 0.40;
        if (zone.toString().equals("ANZ"))
        	cost= 0.30;
        if (zone.toString().equals("LATINAM"))
        	cost= 0.30;
        if (zone.toString().equals("AFRICA"))
        	cost= 0.40;


        return cost;
	}