Hello dear, 

I am providing you the link for the solutions of previous year papers of jee mains -

https://engineering.careers360.com/articles/jee-main-question-paper/amp

Hello.

If are really interested to solve the previous questions then you can but the previous questions book on Amazon or flipkart. You can even down some apps on play store but not sure they work or not and I will provide some random links for that

https://admission.aglasem.com/jee-main-previous-year-question-papers/amp/

https://www.vedantu.com/iit-jee/jee-main-previous-year-question-paper

If these doesn't work better buy the book online.

Hope this is helpful.

Good luck.