I failed in 3 subjects, commerce, economics business and accountancy. How can I pursue Bachelors?

Don't worry for failing in HSC. If you are 18 Years Completed then you can pursue a Graduate (Three Years Course Duration) in Open University Mode through Tamil Nadu Open University, Chennai. They will conduct an Entrance Exam which will be easy for you to clear. Admission has commenced. Best of Luc

You have to pass class 12th for taking admission in graduation. Or, you can do Diploma and after Diploma you can directly get admission in second year of college. Good luck.

First, you can do your class 12th through open school. And later on graduation through correspondence. There are many Diploma courses in the market. You can pursue them as per your choice also.