I had to study 3 AS levels;whereas my cousin was just set mocks for 2 of his subjects and his teachers told them what to study and as a result he had more time to study for his maths AS level. As a result, he got predicted A*AA. On the other hand, I didn't have as much time to study for my maths AS level, but I still gained my A* prediction in the subject. But I had to sit a real chemistry and biology AS to obtain my predictions which were incredibly more difficult.