The reasons are very simple.
#1: Girls manage to inflict more 'maska' on their teachers in lower classes (=grace marks)
#2: They recieve less pressure from parents because people in India never suspect girls or women of being mischievious or bad till they actually see it (so they can trust that their girl is not wasting time).
#3: Girls don't have to worry about boys. If they are dejected, the girl's peer group support her enough to automatically dismiss the person causing dejection as an aggressor.
#4: Girls manage to concentrate more due to the above reasons, knowing that girls are more heavily defended than boys.
#5: Some girls are driven by a competitive spirit to gain more marks than boys.
#6: Most of the subject text books till at least standard X (and perhaps XI and XII) are written by a staff consisting of mostly females (i.e. The content is optimized for the female mind).
Reason#6 and is unavoidable because all of us teach things in the way through which we learnt it. So if we feel explaining in a certain way is easier to understand, others may not think so. And since there is a difference between men and women when it comes to understanding things, we can pretty much guess why girls do better.
But still, boys don't go down to only a 50% success rate when compared with girls. They manage to remain at the top, at least to some extent. What this suggests about the male brain, I will leave you to figure out.
As for higher classes, the textbooks are written by males, and so the male mind understands that stuff better and naturally gives a better performance in the exams. Its all about "Optimization".
![Big Grin :D :D](https://cdn.jsdelivr.net/gh/twitter/twemoji@14.0.2/assets/72x72/1f600.png)