Your underestimating my friend. How could this adolescence obtain an ATAR of 75 when had provided you with raw marks that will align to 80+, and some 90's. He has asked to determine his ATAR based on the marks he think he would attain. So therefore, determine his ATAR of those marks, not his school rank. His cohort performance in the subjects his in play a significant role. Not the school rank. Student won't be repeating, there would be different students, with different knowledge and capabilities.