Hi,
permissions are setup at the server level. Ideally, you should contact your system administrator to make sure that the owner of the folders and files of the website correspond to the apache user. Otherwise, you would have to set the permissions to 664/775 because the apache user is not the owner of the files/folders. Sometimes, the issue can also come from the FTP layer options of the Joomla configuration. Again, these settings depends on how your web server is configured.
I would recommend to follow this tutorial:
www.ostraining.com/blog/joomla/admin-too...nd-file-permissions/