how google show last update in a post in wordpress

i want to know that how google show last update time ie. 1hour ago/55min ago,but the post not updated last one hour may be some 2-3 hours before,here is my screen shots

and the meta tag part is

every time search engine shows some times ago,but the article not update some times ago.can someone help me ,i want to know that what is process to show like this,i submitted to google webmaster for index but it not shown like this

via Chebli Mohamed