For becoming a CA none of the subjects are compulsory. Even student sfrom a science background opt for doing CA later in their life. Therefore you can surely do CA without having economics.

Also, for doing b.com (//b.com) in most of the colleges maths is compulsory but that for b.com (//b.com) hons. .Since you do not have Maths so you can opt for b.com (//b.com) programme instead of hons. Again , for b.com (//b.com) economics is not a compulsory subjevt

Thanks