Flight Sydney Airport departs from Sydney Sydney Airport at 17:15 and arrives at Brisbane Brisbane Airport at 18:45.
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 Wednesday and it would be best to avoid Saturday, as prices are on average 75.75% higher than on Wednesday. (Average prices, based on 2629591 datapoints.)
We have a lot more statistics for flights ZL 368 and between Sydney and Brisbane.