Hi,

The previous year answer  keys of the entrance exam is available on https://bhustudentclub.in/2017/07/24/download-10-years-bhu-uet-previous-year-question-papers/ you can check in the website to find out whether the 2008 answer key is available or not but it's paid one. You haven't specified the subject you are looking for. But there are some sites that provide free access to previous year question papers and answer key. All the best and hope this will help you.