== Compliant Solution

----
public class Fruit 
{
  public double GetCost() 
  {
    return 3.5;
  } 
}

public class Raspberry : Fruit 
{
  public double GetInflatedCost() 
  { 
    return 7.5;
  }
}

// ...
var r = new Raspberry();
var f = (Fruit) r;
Console.WriteLine(r.GetCost());  // prints 3.5
Console.WriteLine(f.GetCost());  // prints 3.5; same code executes every time
Console.WriteLine(r.GetInflatedCost()); // prints 7.5
----
