You are a driver for Ace Mining Company. The boss insists that, every hour on the hour, a loaded truck leaves the mine at \(90.0 \mathrm{~km} / \mathrm{h}\), carrying ore to a mill \(630 \mathrm{~km}\) away. She also insists that an empty truck traveling at \(105 \mathrm{~km} / \mathrm{h}\) leaves the mill every hour on the half hour to return to the mine. One day you begin to count the empty trucks that you encounter, per hour, on your trip to the mill. The next day you decide that loaded trucks are more important, counted on your return trip.