A fast train takes 3 hours less than a slow train for a journey of 60 km. If the speed of the slow train is 10 km/h less than that of the fast train, find the speed of each train.
A) Fast train: 30 km/h, Slow train: 20 km/h
B) Fast train: 40 km/h, Slow train: 30 km/h
C) Fast train: 50 km/h, Slow train: 40 km/h
D) Fast train: 60 km/h, Slow train: 50 km/h