Greeting Aspirant,

The Sixth Subject is considered while calculating Percentage when your marks are low in other Major Subjects.

Example, You got the Following Marks:

1. English: 95 (Major)
2. Accountancy: 85 (Major)
3. Economics: 86 (Major)
4. Business Studies: 90 (Major)
5. Maths: 55 (Major)
6. Banking: 95 (Additional Subject)

So while calculating Aggregate Your best of 5 (Aggregate= 90.5%) or Best of 4 (Aggregate = 91.4%)  will be Taken.

Hope My Answer Helped You.

Best Of Luck For Future.

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