How many hours does it take to fly to Sydney from Perth?

A random search for flights from PER to CDG shows: OPTION 1: 20hr 15min via KUL

PER - KUL Malaysia Airlines Flt 124 Dep 04:25pm 26Jun,Fri

KUL - CDG Malaysia Airlines Flt 020 Dep 11:35pm 26Jun,Fri

Flight Duration: 18hr 45min; Layover Time: 1hr 30min; Total Trip Time: 20hr 15min

1-way Economy fare US$476.oo + Taxes & Fees US$264.oo OPTION 2: 20hr 10min via DXB

PER - DXB Emirates Airlines Flt 425 Dep 06:00am 26Jun,Fri

DXB - CDG Emirates Airlines Flt 075 Dep 03:00pm 26Jun,Fri

Flight Duration: 18hr 10min; Layover Time: 2hr 0min; Total Trip Time: 20hr 10min

1-way Economy fare US$1,351.oo + Taxes & Fees US$56.oo OPTION 3: 20hr 35min via SIN

PER - SIN Qantas Airways Flt 0071 Dep 03:30pm 26Jun,Fri

SIN - CDG Qantas Airways Flt 3977 Dep 10:55pm 26Jun,Fri

Flight Duration: 18hr 35min; Layover Time: 2hr 0min; Total Trip Time: 20hr 35min

1-way Economy fare US$1,529.oo + Taxes & Fees US$64.oo