21 free video lectures on Caselets (Quant-Based) for CAT DILR (DILR), taught step by step by Shweta Arora. Free to watch, no signup.
Caselets (Quant-Based) sits in the DILR area of the CAT DILR syllabus. Work through the lectures first, then move to the practice set — the concepts stick far better once you have attempted questions under a timer.