Scanned copy of previous year question paper can lead to copy right issues.
Even typing the questions is not a very good idea because many websites would have already posted the question papers.
I would however suggest you to combine questions from last 2-3 year old papers and design a model paper and mention it there that "The paper is a model paper which contains questions from last 2 - 3 yr old papers and is not the exact paper of any year". This way the students would get to know some questions from last few years and MPS would also be saved from getting in duplicate or copy right issue.
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