A train leaves San Diego at 1:00 PM. A second train leaves the same city in the same direction at 4:00 PM. The second train travels 78 mph faster than the first. If the second train overtakes the first at 6:00 PM, what is the speed of each of the two trains?

1 answer

speed of slower train --- x mph
speed of faster train --- x + 78 mph

time of slower train to overtaking = 5 hrs
(form 1:00 to 6:00)
time of faster train to overtaking = 2 hrs

5x = 2(x+78)

solve for x