How many races has the class 'GT'?
select count(*) from race where class = 'GT'
What about without that class?
select count(*) from race where class != 'GT'
What are the track names of them?
select name from track except select t2.name from race as t1 join track as t2 on t1.track_id = t2.track_id where t1.class = 'GT'