Maharashtra Board

There are multiple websites providing the previous year question papers of different board exams. Self Studys, being one of them providing it for free provides both the PYQs and mock test as well. Mock tests is organised in the same way as the original question paper is structured and it gives more chances for practice. Another site called 'Maharasthrastudy.com' also provides question paper with answers as well. This sites are applicable to another courses and subjects as well. Just google, you will have access to lot more websites both paid and free. 

As far as my knowledge you can change your stream from Science to commerce. But you need to contact the school officials as they are the one who can guide you with the correct information. For more accurate information you should contact to your exam board office or website, I hope it helps you.

 Yes, candidates who fail in 3 or less than 3 subjects are eligible to appear for Maharashtra HSC supplementary exams.