Flight Sydney Airport departs from Sydney Sydney Airport at 18:35 and arrives at Brisbane Brisbane Airport at 20:05.
The flighttime is about 1h 30m. The distance travelled ("as the bird flies"): 680 Km. So the average speed is roughly 453 Km.
The best day to arrive at Sydney is Sunday and it would be best to avoid Wednesday, as prices are on average 188.86% higher than on Sunday. (Average prices, based on 2624543 datapoints.)
We have a lot more statistics for flights QF 546 and between Sydney and Brisbane.