Hey.

The Best of four percentage for admission in DU for Bcom hons course includes marks in any one Language subject (English, Hindi) and marks  from 3 core subjects. In case of Bcom the core subejcts are- Mathematics, Accountancy, Business Studies/Commerce Economics.

If you add a subject from other than any core subjects and the given language then 1% will be deducted from the aggregate percentage. So you can add Hindi without any deduction of marks. But if you add Phy-ed instead of a core subject then 1% marks will be deducted.

Best of luck