i think best of two will be taken 

Hi Akash,

You have to choose one. If you choose to give 64 as your Chemistry marks then for the remaining subjects, you have to give the previous year marks which means your overall percentage becomes less i.e., 62%. If you choose to give 50 as your Chemistry marks then for the remaining subjects, you have to give current year marks which means your overall percentage increases i.e., 72%. Hence it is advisable that you give current year marks.

Thank you and all the best for your future.