Hi Srierag,

Index marks calculation:

Marks scored in the subject you want to pursue your graduation in, in this case food technology/nutrition or whichever subject you had in your 12th standard + 10% of the total score of 'best of 5' subjects in 12th board exam.

Eg:

Your best of 5 is = 400

So 10% of 400 = 40

Now, you scored in nutrition or food science in 12th board exam = 50

So, your index marks = 50 + 40 = 90

Hope you understood. All the best!