Colleges in Delhi

No.
B.Sc mathematics is a regular course and fully approved by UGC.

Hello Radhika,
IP University of Delhi has quite a reputation in the country and not only in Delhi. You must attempt to get admission here if possible. Do not hesitate.

Do BBA from Asian School of business.
You'll also get a college life and environment instead of sitting at home.

You need to fill the application basis of expected percentage. The cut-off admission will be done after results are out.

Hamdard Institute of medical sciences and research, JNU, and Rajiv Gandhi Paramedical Institute.

Admission in IIMs /FMS / IIT depends a lot on the score you achieve at CAT. The institutes mentioned by you are among the top ranked ones and to seek admission in any of them, you should air for scoring at least 98+ percentile score at CAT and also, do well at the Personal Interview for seeking admission.