I'm expecting this code to return true but it doesn't ? What am I missing here.

  string xml = @"<data><e id=""NUM_CPUS"">1</e><e id=""ACE_PRESENT"">1</e></data>";
  XPathDocument doc = new XPathDocument(new StringReader(xml));
  string expr = "(id('NUM_CPUS'))>=1 and (id('ACE_PRESENT'))=1";
  XPathNavigator nav = doc.CreateNavigator();

  XPathExpression query = nav.Compile(expr);

  object result = nav.Evaluate(query);
  bool b = bool.Parse(result.ToString());

  if (!b)
    throw new Exception("Should be true");