I am a GCE A-Level student, as in A-Level certificate grades and percentage uniform mark is provided in the certificate, not the total mark achieved for the subject.

I got 48 in General Paper, 67 in Chemistry, 73% in Physics and 68% in Mathematics. So how do you calculate the percentage?
(48+67+73+68)/400 = 64 %

I am wondering whether I will be eligible for Dasa or not?
also, do I need to cross 60 % above in each subject or in aggregate?