Distance = (speed) x (time)
Distance = (3 x 10⁸ meter/second) x (1 hour)
Distance = 3 x 10⁸ meter-hour per second
Distance = 3 x 10⁵ kilometer-hour per second
Hmmm. That answer is perfectly correct and totally useless. We have no idea how far one meter-hour per second is. It's a unit we never use. We'd better convert the answer to a unit of length that we use every day.
(3 x 10⁵ km-hour/sec) x (3,600 sec/hour) =
(3 x 10⁵ x 3,600) (km-hour-sec/hour-sec) =
1.08 x 10⁹ km
THAT's it ! A pulse of light in vacuum travels 1.08 billion km in one hour.
