The diameter of the Milky Way disc is approximately 9x1020 m

The diameter of the Milky Way disc is approximately 9x10^20 meters. How long does it take light, traveling at 10^16 m/year to travel across the diameter of the Milky Way?
Any help with this question would be appreciated.

Solution

9*10^20/10^16
9*10^(20-16)
9*10^4
90,000 YEARS TRAVEL TIME ACROSS THE MILKY WAY DISC.