Wordpress re-direct with junk URL affecting page rank

Hey guys, I tested my site with google page speed one of the things mentioned was “Avoid landing page redirects” and there are 3 URLS below… I have noticed this issue in a some other sites too… so i hope it will help those people too…

http://mywebsitename.com/
http://mywebsitename.com/XkOPZ/
http://www.mywebsitename.com/

How can this be sorted?

TIA