you need internet connection for dis:
go to applications-accessories-terminal: and write the foll command dere:
$ apt get install unrar
this Command Installs unrar..
now again start the terminal:
again in terminal :
go to the directory where .rar file is present.
if your file is in Documents folder do as Follows in terminal
$ cd Documents
$ unrar x filename.rar
close the terminal and go to the Documents or whichever folder ur rar file was in and the extracted folder will be present..
Extraction will b Done..