Aquawhite
Retiring
If this is actual solid revision and study (not homework or due tasks that actually have to be done)... something from your own accord as your own notes/practice... then yes. 3.5 hours per week of each subject sounds very sufficent! ideal, although might be hard to manage when the workload builds up :S (try 2.5 per subject to start with if you havn't started)...
If you don't exactly get 'homework' then definitely 3.5 hours sounds good.
If you don't exactly get 'homework' then definitely 3.5 hours sounds good.