Usage Of Ref and Out Parameters

class RefOutParams
    {

        void Withtax(ref decimal amt)
        {
            amt = amt + (amt * 12.4M / 100);
        }

        void TaxValue(out decimal tax)
        {
            tax = 12.4M;
        }
        static void Main(string[] args)
        {
            RefOutParams p = new RefOutParams();
            decimal amount=50;

            p.Withtax(ref amount);
            Console.WriteLine(amount);

            decimal tax;
            p.TaxValue(out  tax);
            Console.WriteLine(tax);

        }