ranges from 30 mins to up to an hr depending on traffic and what time you are travelling.. i used to have 10am classes and it used to always take 30 mins if i leave at 9am compared to 45-50 mins if i leave at 8am. From Eastern subrubs near la perouse.
Around 40 mins by train + walking from Central for me (I live on the East Hills line)
There's nothing more awkward than walking to the station from uni to realise that there's a lecturer walking the same way just behind you... Then said lecturer recognises you and waves as they walk past.
For me, anywhere from 50 minutes to 1.5 hours from Gordon (north shore). Bus + train + walking + waiting generally equals 1.5 hours. Train + station to UTS = 50 minutes, thereabouts.