Question

Two trains travel in the same direction on parallel tracks. Train A starts out 50 kilometers ahead of Train B. Train A travels 90 kilometers per hour and Train B travel 100 kilometers per hour. In how many hours will the trains be in the same place?

Is the answer 5 hours?

Answer 1

yes,

easy way:
the faster train is gaining on the slower train at 10 km/h
it has to make up 50 km, so time = 50/10 or 5 hrs.