Both offices are open 10:30–18:00 Adelaide time — 7.5 hours together.
11:00 you → 09:30 Singapore
12:00 you → 10:30 Singapore
13:00 you → 11:30 Singapore
09:00→07:30outside Singapore working hours
10:00→08:30outside Singapore working hours
11:00→09:30Singapore is at work
12:00→10:30Singapore is at work
13:00→11:30Singapore is at work
14:00→12:30Singapore is at work
15:00→13:30Singapore is at work
16:00→14:30Singapore is at work
17:00→15:30Singapore is at work
Working hours assumed 09:00–18:00 local. Offsets include daylight saving where it applies, so this shifts through the year.