Use the formula Distance = Rate x Time to solve the problem. The distance is 200 miles and the rate is 100 mph. Let t be the time the two trains travel.

Now we have 200 miles = (100 mph)t.

So t = 200 miles / 100 mph. t=2 hours.

The trains meet at 8:00 pm.

Using the same formula (Distance = Rate X Time) we can now determine how far each train traveled.

Freight train. d = (15 mph)(2 hours). d=30 miles.

Passenger train. d = (85 mph)(2 hours). d=170 miles.

The trains meet at Greenville, which is 30 miles from Unionville and 170 miles from Stonesboro.