string s1 = "9";
string s2 = "82";
string s3 = "24";
long seconds = Convert.ToInt64(s3) + Convert.ToInt64(s2) * 60+Convert.ToInt64(s1)*3600;
DateTime startDateTime = DateTime.Today;
DateTime date = startDateTime.AddSeconds(seconds);
Console.WriteLine(date.ToString("hh:mm:ss tt", System.Globalization.CultureInfo.InvariantCulture));
Console.ReadKey();