using System;

//calling base versions of method

 class CustomerAccount

{

public  decimal CalculatePrice()

{

// implementation

return 1.00m;

}

}   

class GoldAccount : CustomerAccount

{

public decimal CalculatePrice1()

{

return CalculatePrice() * 0.9M;

}

}                   

public class Program

{

    public static void Main()

    {

      GoldAccount ga = new GoldAccount();

      Console.WriteLine(ga.CalculatePrice1());

    }

}

​