Central Board Of Secondary Education [CBSE] — Maths

I am student of CBSE 12th (Roll no.[protected]
CBSE have given me compartment in Maths.
Regarding to your policy you gave marks according to this:
30% of 10th, 30% of 11th and 40% of 12th
I got 51 in 10th then my 30% is 15.3
I got 51 in Theory in 11th then my 30% is 15.3
The total is 30.6 (31 approx) but in my mark sheet I got 21 it means its a technical error in calculation.
I am getting pass only with my 10th and 11th marks then how can I get Compartment in Maths. Where is my 12th 40% marks?

I request you to do re-calculation.