In total hours I've put aside, probably some rudiculous number, but the actual hours of meaningful study is miniscule by comparison
But hey, it's the School Certificate, and one of it's purposes is to get us into the habit of studying. IMO, the only bad thing that can come from me getting poor marks is the embarassment come Christmas time when all my relatives want to know what I got in the SC (and of course they've all got high expectations, sucks to have smart siblings).