Hey.

There is no such course of Bsc LLB of 3 years. There will either be a course for 5 years which is integrated- Bsc+ LLb. Or there will a 3 year LLb course only and in this case you'll have to do any undergraduate degree like Bsc, BA etc at first which will also be for 3 years and will take you a total of 6 years. In the former case of an integrated course you'll have subejcts of both Bsc and Law in the 5 years. Mostly course structures are such that you complete all bsc subjects and a few law subjects in the first 3 years and then only law subjects in the last 2 years. But in any case you can't pursue the course of BSc+ LLB together in 3 years.

Best of luck