Should I vote to close strictly the newest one, or the one that has the most constructive content?

What if both have constructive content, as is the case with these two questions?

 - [bind software to different network interfaces][1]
 - [How can an application (like Firefox) be forced to use a certain network interface?][2]


  [1]: http://askubuntu.com/questions/4872/bind-software-to-different-network-interfaces
  [2]: http://askubuntu.com/questions/25778/how-can-an-application-like-firefox-be-forced-to-use-a-certain-network-interfac