using System;
using System.Xml.Linq;
using System.Xml;
public class Program
{
public static void Main()
var xml = @"<Root>
<Marys_basket numFruits=""2"">
<Fruit name=""Mango""/>
<Fruit name=""Papaya""/>
</Marys_basket>
<Jons_basket numFruits=""0"" />
<Bobs_basket numFruits=""1"">
<Fruit name=""Apple""/>
</Bobs_basket>
</Root>";
var doc = XDocument.Parse(xml);
XElement basket = doc.Root.Element("Marys_basket");
basket.FirstAttribute.SetValue((int)basket.FirstAttribute + 1);
Console.WriteLine(doc.ToString());
}