Adelaide's time difference to Melbourne's is due to the fact that it lies further to the west and so is slightly behind in terms of when the sun rises and sets. Broken Hill in New South Wales is also on Adelaide's time zone because it lies so far to the west of that state.
Answer
Australia's time zones are in dire need of overhauling. Adelaide (Central Standard Time) should perhaps be one hour, not half an hour, behind EST. There is a strange time zone on the WA/SA border (right in between WA & SA time, so 45 minutes behind Adelaide time, called Central Western Time, which is semi-official, otherwise sunset would be at 3.30pm in winter.
Because there different places?
If it is 3pm in Adelaide, it is 3:30pm in Melbourne.
9:00 Adelaide is half an hour Behind Melbourne
Adelaide is half an hour behind Melbourne time, so it would be 1:30.
The flight is just over an hour long in actual time (remember that Melbourne is half an hour ahead of Adelaide's time.)
There is half an hour's time difference between Melbourne, which is in the state of Victoria, and the state of South Australia. Melbourne is ahead by 30 minutes, meaning that, when it is 12:00 in Melbourne, it is 11:30 in Adelaide.
11:30
1:30 pm
11:30
Adelaide, the capital of South Australia, is northwest of Melbourne.
It's 1:30 PM CST.
Adelaide is closer.
There are several major routes from Melbourne to Adelaide, but the most logical is the Princes Highway.