title: Why can I not use Tuple in C#, Visual studio 2010?
body: <p>I have the following installed: 
  Visual Studio 2010 Professional,
  .NET 4.0.30319</p>
  
  <p>In my program i added the using system and collections generic
  but I can not seem to use Tuple ( Using C# )</p>
  
  <p>Can anyone tell me why ?
  Thanks</p>