Write a C# Sharp program to calculate what day of the week is 40 days from this moment

using System;
public class Example9
{
   public static void Main()
   {  System.DateTime today = System.DateTime.Now;
    System.Console.WriteLine("Today = "+System.DateTime.Now);
    System.TimeSpan duration = new System.TimeSpan(40, 0, 0, 0);
    System.DateTime answer = today.Add(duration);
    System.Console.WriteLine("{0:dddd}", answer);
   }
}