Wow in Australia it's 9 - 3 pretty standard.. although some schools have seniors (yr 11 and 12) starting 7:45 and finishing at 1. With 6 weeks off at christmas and 6 weeks off during the year. I think I prefer our hours!
In terms of hours, thats 6 hours a day (minus 1 hour for lunch) so 5 hours of actual school work.