A good answer might be:

The blanks are filled in, below.

Adding the Interface

The child class Food extends the parent class. It uses super to use the parent's constructor and the parent's display method.

class Food extends Goods
{
  double calories;

  Food( String des, double pr, double cal)
  {
    super( des, pr );
    calories = cal ;
  }

  void display()
  {
    super.display( );
    System.out.println( "calories: " + calories );
  }
}

Here is Taxable:

The Taxable interface looks like this:

interface Taxable
{
  final double _____ = ______ ;
  double ___________() ;
}

The final says that what follows is a constant, not a variable (variables are not allowed in interfaces.) In fact, the final can be omitted since the identifier that follows will automatically be a constant. The " = value " cannot be omitted.

The method declaration (in the second line) is public by default.

QUESTION 8:

Fill in the blanks.