B.A

yes it's depends upon the cut offs

yes you will get admission.

There are some chances of getting BHU. You can try to get admission.
https://googleweblight.com/i?u=https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor&grqid=MGYL-eCx&s=1&hl=en-IN
Here, I am sharing college predictor link. You can go through to know about the college you can get.
Good luck.

Yes maths marks are mandatory for BA Hons in economics in DU.

Three Simple Steps for Applying Online for BA in DAV centenary college:
Fill in the basic details and note down the System generated Registration ID and Password.
Fill the online Application Form, upload your photograph, signatures and the required documents.
Make payment of the Admission Processing cum Admission Brochure Fee through Credit /Debit Card/Net Banking.

You can directly visit your university with your documents, like mark sheet of your graduation. They will provide you degree within 80 days.

If you want to pursue B.A vocational, then you have a chance in DU as it offers at minimum 40%. You must confirm there as well because at 45 no college will be eligible to you.