using System;

using System.Collections.Generic;

using System.Linq;

using System.Xml.Linq;

public class Program

{

    public static void Main()

    {

        Fares first = new Fares();

        first.Code = "ADT";

        first.Amount = 47.4F;

        first.Quantity = 3;

        Fares second = new Fares();

        second.Code = "ADT";

        second.Amount = 1.5F;

        second.Quantity = 1;

        Fares third = new Fares();

        third.Code = "ADT";

        third.Amount = 1.5F;

        third.Quantity = 1;

        List<Fares> fareList = new List<Fares>();

        fareList.Add(first);

        fareList.Add(second);

        fareList.Add(third);

        IEnumerable<Fares> enFareList = fareList;

        float sum = enFareList.Where(c => c.Code.Equals("ADT")).Sum(c => (c.Amount * c.Quantity));

        // Old

        XAttribute sumAmountOld = new XAttribute("Amount", sum);

        // New

        XAttribute sumAmountNew = new XAttribute("Amount", sum.ToString("0.00"));

        Console.WriteLine(sumAmountOld.Value);

        Console.WriteLine(sumAmountNew.Value);

    }

    public class Fares

    {

        public string Code { get; set; }

        public float Amount { get; set; }

        public uint Quantity { get; set; }

    }

}

​

​