SSC CGL Preparation

For Masters, you have to crack the entrance exam, you can pursue Masters in finance or marketing wherever your interest lies but having a B.Com background, you would have basic finance related knowledge which you could apply in MBA in finance. Getting into top B-Schools should be your priority.

Actually not, but there are some differences in pattern of exam the level of CAT exam is higher than the level of SSC CGL exam. CAT is more concept worthy examination where are in the SSC CGL speed of your problem solving matters as there are less time. And there are the GK portion too in the SSC CGL which are not in the CAT exam.

For doubts in aptitude section, I would suggest you to watch study smart and Mahendra guru channel videos and few apps are also there like oliveboard, testbook, Adda247, govjobadda, gradeup, etc.

Yes, you can do your Master degree from IGNOU through distance.