A radio wave travels at the speed of light, which is equal to approximately 300,000 km/s.
So, to travel a distance of 998.25 km, the time needed is:
[tex]\begin{gathered} distance=speed\cdot time\\ \\ 998.25=300000\cdot time\\ \\ time=\frac{998.25}{300000}\\ \\ time=0.0033275\text{ seconds}\\ \\ time=3327.5\text{ microseconds} \end{gathered}[/tex]Therefore the time required is approximately 3327.5 microseconds.
