Finding a basis for column space from pivot columns — IITM BS previous year questions

Finding a basis for column space from pivot columns is part of Rank and Dimension Using Gaussian Elimination, Week 4 in Mathematics 2. Prasnya files every IIT Madras BS previous year question from this subtopic here, each one with a worked explanation. Take the whole set as a timed mock and you get accuracy, pacing and per-question analysis back.