Answer:
The two trains are closing the initial distance between that of 280 miles by the sum of their two speeds. 80mph + 60mph = 140 mph. With the speed that the distance between the trains is closing, we can divide the starting distance to find out the number of hours until the trains pass. 280 miles / 140 mph = 2 hours. Since the trains left at 3:00 and will pass each other in 2 hours, they will pass each other at 5:00.
Explanation: