interface Taxable
{
  final double taxRate = 0.06 ;
  double calculateTax() ;
}

Adding Toy

taxRate is a constant. It must be set to a value.

Here is a partial definition of Toy. Recall that it:

• Has a parent, Goods.
• Adds an instance variable, minimumAge.
• Is taxable.

class Toy extends Goods  
{
  protected int minimumAge;

  public Toy( String des, double pr, int min)
  {
    super( des, pr );
    minimumAge  = min ;
  }

  public String toString()
  {
    return super.toString() + "minimum age: " + minimumAge );
  }

  public double   // implement a method in the interface
  {
    return price *  ;
  }
}