what you guys are saying about ranking and internal and external marks is a bit misguided.
The internal mark that you received is irrelevant, your rank is all that matters. What happens is that they attribute the external mark to the corresponding rank as the internal mark. E.g. rank 3 gets 45/50 in the external, and rank 2 gets 40/50 in the external. Rank 2 will take rank 3's mark so... rank 2 will end up with 45 and rank 3 with 40, for their internal marks. However they will still retain their OWN external mark. Which means that rank 2 will get 45/50 for Internal and 40/50 for External, ther final mark will be the average of the two. This applies to all the marks.
This is the only way the BOS can give equal marks across the state, because otherwise some teachers could mark harder than others, resulting in lower marks for ultimately better students. This goes for all the subjects.
Hope that helps, and their are some circumstances were the original internal mark does come into consideration, but for these purposes they are irrelevant.