Colleges in Delhi

You can give various exams for MBA colleges, such as CAT. But you should prepare for that entrance exams because it is not an easy task and obviously it is not impossible. Go through the syllabus have a look about the environment of the competition. Be mentally prepared. And finally, if you want, you'll be there definitely.

No, it wouldn't as far as you have a recent character certificate of what were you up to during the gap year.

It is clearly mentioned in the guidelines of Delhi University that you can't opt for economics (Hons) if you haven't studied maths till 12th. You can't opt B.Com (Hons) too but you can go for B.Com programme.

The direct method is the merit-based method, which means you get admission based on your score in graduation, in your case 84.3%. Exam-based method is where you have to appear for an entrance exam conducted by the college itself and your admission would depend on the marks you score in this entrance. You can either go for Masters (M.Com/ MA in economics) or GBO (which is equivalent to a MBA).

Usually, a minimum of best of four 97.5%/97.8% is required. That's the minimum. Scoring a 98 or above would be on the safer side.
Maths is required as one of your subjects in +2, and you need to pass in it. However, it's usually not calculated in the best of four.

Usually, the cut-offs for general category is close at 98%/97.8% maximum. But if you have any reservations, you do have chances to get in, depending on the session's cut-offs.

SRCC offers PG in Global Business Operations (GBO) which is equivalent to an MBA. Admission is done through entrance and group discussion. An exam is conducted by the college and selected students on the basis of merit are invited for the GD. Here are some useful links-
http://www.srccgbo.edu.in
http://www.srcc.edu/academics/admissions/admission-procedure/postgraduate
http://srccgbo.edu.in/Courses.php