With 84 marks in SC category will I qualify for JEE Advanced? Rank predictor is showing that I'll qualify.

Yes Rocky, for qualifying in JEE Advanced you just need 40-60 to clear the cutoff. This is only for SC/ST.For General category its around 120. But do remember that qualifying JEE Advanced doesn't bring you great choices among the top iits and nits. I really hope you can do more the cutoff and wish to see you in top IIT's.All the very best:)

Actually I lost 25 marks due to my unfamiliarity with Computer Based Test where I didn't to click "Save and Next" option while changing my answer in paper.

Thanks for your kind wishes. I hope to perform well in Advanced.

In JEE Mains.

That's really great, all the best perform well in your jee advanced. Next time, you take any test you make sure you click save and next option. It's compulsory for submission of your answer.