Question

The first train leaves a station at a speed of 72 mph. The second train leaves the same station 1 hour later and follows the same route at a faster rate of 90 mph. In how many hours will the second train catch up with the first?

Answer 1

Equation:

distance = distance

72x = 90(x-1)

72x = 90x-90

18x = 90

x = 5 hrs

x-1 = 4 hrs