I have the following site themobileinfo dot com applied for adsence and they sent this letter : Not I didn't understand what was my fault ?
If your site is just regurgitated content Google will not approve your account. Try getting some original content and moving forward.
Most of the articles are written by me, Copyscape found 1-3% match But other 2 writer's post has 15% match in copyscape, so should I delete them and apply again to google ?
Dude, check out Google Adsense guidelines, before you apply again. Anyways mention your location, if you already had the site for more than 6 months, so that will help others to give some tips, which may or may not work. To approve or not, everything is Google's hands.