Assume each of the presidents says that he is five feet from the bulb. How fast must the train be going for the observers on the platform to find that the President of Fowardland received the light signal one nanosecond ($=10^{-9}\,\textrm{s}$, which we will often write as 1 ns) before the President of Backwardland? (Use $c = 1$ foot/ns and round your answer to two significant figures.)

Now suppose the platform observers measure a much longer time difference between the two signings – a time difference of 5 hours and 12 minutes. Also assume that the platform observers measure the speed of the train to be ${12 \over 13} c$ to their right. According to the platform observers, how far apart are the two presidents? Give your answer in units of light-hours (which we will often abbreviate as lt-hours).