Hello,

There are many private sites which provide with the answer key online,you can get them by doing a simple google search.

But I would recommend you to search for "Aiish Baslp solved paper" on youtube as well as you will get many videos that will provide the solution of each and every question,with explanation of each concept which would be beneficial for you.

You can check out the previous year paper from this official link also- http://aiish.ac.in/question-paper.html

All the Best!