Jason is correct. both URLs would end up at the same page. But my question would be, why? They only reason I can imagine is to split the sources pointing to the page. But there are other ways to do this.
http://sub.exmple.com/path-to-my-page.html is the landing page
http://sub.exmple.com/path-to-my-page.html?ad=A is used for advertisement A
http://sub.exmple.com/path-to-my-page.html?ad=B is used for advertisement b
Both advertisements will end up at the same page. You can trigger/filter on the ?ad= to update lead source for instance.