Hi
Budhaditya1984,
Reading material:Download free gmatclub quant guide. Finish every word of it.
If you can buy manhattan guides then finish every word of them.
Practice:Gmatclub Quant CATs (You can o quizzes also - 1500 questions in pool)
get Math Revolution 100 questions to practice as add-ons
following link is an ocean of questions to choose from as per the need:
https://gmatclub.com/forum/viewforumtags.phpofficial material: All qestions from ALL OGs, GMATPrep CATs and Question pack.
CATs:Gmatclub Quant CATs
MGMAT CATs (comes free with
MGMAT guide)
MathRevolution
Whenever you come across any question just search it on google or use gmatclub search, you'd most likely find it on gmatclub along with BUNUEL's explanation for it :D
Follow
Bunuel to solve the questions/solutions posted by him everyday.
If you do all of the above things and
ALSO REVISE REVISE REVISE then Q50-51 is not far

Hope it helps. Let me know if you need any further information.
Happy Studying