C# Why method performs two times?

Question

Here is the full code (skip it if you don't need it):

using System;
namespace Laboratory_work
{
    class Program
    {   
    //some code
    public class Engineer: WhiteCollarWorker, Method1, Method2
    {
        public int YearExperience{get; set;}
        public bool BachelorDegree{get; set;}
        public bool MasterDegree{get; set;}
        public override string InformationOutput(Person obj)
        {
            return base.InformationOutput(obj)+"Experience — "+YearExperience+" year(s)\n"+
                "Bachelor Degree — "+BachelorDegree+"\n"+
                "Master Degree — "+MasterDegree+"\n";
        }
        public int WorkOffer()
        {
            if (Age>=21 && YearExperience>=1 && BachelorDegree==true)
            {
                Console.WriteLine("\nYou may be offered a job.");
                return 1;
            }
            else
            {
                Console.WriteLine("\nUnfortunately, there is no job for you.");
                return 0;
            }
        }
        public int Invitation()
        {
            if(WorkOffer()==1)
            {
                Console.WriteLine("Dear "+Name+" "+Surname+", soon you will receive\n"+
                                  "an email with date and time of your interview\n"+
                                  "at out company.Thank you for your CV.");
                return 1;                  
            }
            else
            {
                Console.WriteLine("Dear "+Name+" "+Surname+", unfortunately, you are\n"+
                                  "not suitable for this position. Than you for your CV.\n");
                return 0;  
            }
        }
    }

    //some code

    public static void Main()
    {
        const int N=10;
        int Count=0;

        var persons1=new Engineer[N];
        for (int i=0; i<10; i++)
        {
            persons1[i] = new Engineer();

            Delegate DELnum1=persons1[i].WorkOffer;
            Delegate DELnum2=persons1[i].Invitation;
            Delegate DDEL=DELnum1+DELnum2;

            Console.WriteLine("\n\nENGINEERS\n________\n");
            Console.WriteLine("Input information of a person");
            Console.Write("Name: ");
            persons1[i].Name=Console.ReadLine();
            Console.Write("Surname: ");
            persons1[i].Surname=Console.ReadLine();
            Console.Write("Age: ");
            persons1[i].Age=int.Parse(Console.ReadLine());
            Console.Write("Occupation: ");
            persons1[i].Occupation=Console.ReadLine();
            Console.Write("Computer (true or false): ");
            persons1[i].ComputerAvailable=bool.Parse(Console.ReadLine());
            Console.Write("Experience (in years): ");
            persons1[i].YearExperience=int.Parse(Console.ReadLine());
            Console.Write("Bachelor Degree (true or false): ");
            persons1[i].BachelorDegree=bool.Parse(Console.ReadLine());
            Console.Write("Master Degree (true or false): ");
            persons1[i].MasterDegree=bool.Parse(Console.ReadLine());

            DDEL(); 

            Count++;
            Console.WriteLine("Do you want to continue? (Print 'OK' or 'NO'.)");
            string answer;
            answer=Console.ReadLine();
            if (answer=="OK"||answer=="ok") continue;
            else break;
        }
        for(int i=0; i<Count;i++)
        {
            Delegate DELnum2=persons1[i].Invitation;
            Console.WriteLine("\n\n#"+(i+1));
            Console.WriteLine(persons1[i].InformationOutput(persons1[i]));
            if (DELnum2()==1) Console.WriteLine("\nAccepted for work.");
            else Console.WriteLine("\nNot accepted for work.");
        }
        //some code
        Console.WriteLine("\nPress any key to continue . . .");
        Console.ReadKey(true);
    }
    }
}

I create instances of delegate and use them to perform two methods at ones. Delegate:

public delegate int Delegate ();

Methods (in class Engineer):

public int WorkOffer()
        {
            if (Age>=21 && YearExperience>=1 && BachelorDegree==true)
            {
                Console.WriteLine("\nYou may be offered a job.");
                return 1;
            }
            else
            {
                Console.WriteLine("\nUnfortunately, there is no job for you.");
                return 0;
            }
        }
        public int Invitation()
        {
            if(WorkOffer()==1)
            {
                Console.WriteLine("Dear "+Name+" "+Surname+", soon you will receive\n"+
                                  "an email with date and time of your interview\n"+
                                  "at out company.Thank you for your CV.");
                return 1;                  
            }
            else
            {
                Console.WriteLine("Dear "+Name+" "+Surname+", unfortunately, you are\n"+
                                  "not suitable for this position. Than you for your CV.\n");
                return 0;  
            }
        }

This is how I connect this methods in one delegate (in cycle):

    Delegate DELnum1=persons1[i].WorkOffer;
    Delegate DELnum2=persons1[i].Invitation;
    Delegate DDEL=DELnum1+DELnum2;

And then use them:

DDEL(); 

But in output I have two messeges 'Unfortunately, there is no job for you'. Why? Can anyone explain it? Output. Excuse me for random input.

Answer 1

The Invitation method calls the WorkOffer method in the if condition.

This means that DDEL calls WorkOffer directly, and also indirectly through Invitation.

With that in mind, you don't need to call WorkOffer directly through the delegate

Answer 2

The answer is quite simple:
You are calling WorkOffer twice. Once in the delegate and once in Invitation.