That's odd. The archive manager should work with RAR files by default. I just tested it with an example RAR file from here: https://code.google.com/p/suddendeath/downloads/detail?name=example.rar&can=2&q= Does that one open for you? If it does, maybe the RAR file you're trying to open is corrupt? Are you getting a CRC error or anything like that? Once you get the PDFs extracted, you can double click on them in the file manager and they will open with Document Viewer, which is technically called Evince. But your problem is that you can't extract them. Check the error that you get when attempting to extract. If it's a CRC error or something along those lines, try downloading the RAR file again. If you still get the error, contact the vendor and have them re-post the file.