using System;

public class Program

{

    delegate double CalculateSimpleInterest(double p1, double p2, double p3);

    static CalculateSimpleInterest dObjSI = getTotalInterest;

    public static void Main()

    {

        dObjSI.Invoke(120, 1, 3.25);

        Console.WriteLine("==============================");

        //dObjSI = new CalculateSimpleInterest(getInterestRatePerYear);

        dObjSI += getInterestRatePerYear;

        dObjSI.Invoke(130, 120, 1);

        Console.WriteLine("==============================");

        //dObjSI = new CalculateSimpleInterest(getInterestTimeSpan);

        dObjSI += getInterestTimeSpan;

        dObjSI.Invoke(140, 120, 3.25);

        Console.WriteLine("==============================");

​

    }

    static double getTotalInterest(double p, double t, double r)

    {

        Console.WriteLine("getTotalInterest is {0}", (p * t * r) / 100);

        return (p * t * r) / 100;

    }

    static double getInterestRatePerYear(double SI, double p, double t)

    {

        Console.WriteLine("getInterestRatePerYear is {0}", (SI * 100)/(p * t));

        return (SI * 100)/(p*t);

    }

    static double getInterestTimeSpan(double SI, double p, double r)

    {

        Console.WriteLine("getInterestRatePerYear is {0}", (SI * 100)/(p * r));

        return (SI * 100) / (p * r);

    }

}