In Australia, our entry to universities is dependent largely on a grade resulting from our schooling. The grade is based on two parts: in school assignments/tests and a large end of school exam block. The thing is that the assignment/test part scales based on how well the average student from your school/class went on the final exam.

Wealthy students get the best grades since their parents send them to expensive schools designed to maximise this system. They then get into the "best" universities.