Answer:
997.319138 seconds
Explanation:
Speed = Speed of light = [tex]3\times 10^8\ m/s[/tex]
Converting distance to m
[tex]1\ AU=149597870700\ m[/tex]
One way trip
[tex]Time=\dfrac{Distance}{Speed}\\\Rightarrow Time=\dfrac{149597870700}{3\times 10^8}\\\Rightarrow Time=498.659569\ s[/tex]
Two way trip would be
[tex]2\times Time=2\times 498.659569=997.319138\ s[/tex]
The round trip would take 997.319138 seconds