A train leaves little rock, arkansas, and travels north at 90km per hour. Another train leaves at the same time and travels south at 90km per hour. How long will it take before they are 720 km apart?
Since the two trains are heading in opposite directions, they are separating at 90km/hr+85km/hr=175 km hr. 700 km/175 km/hr= 4 hrs. The trains will be 700 km apart in 4 hours.
