Two trains leave a station One train is traveling north at 6

Two trains leave a station. One train is traveling north at 60mph and the other is traveling south at 54mph. In how many hours will the two trains be 342 miles apart?

Solution

60t+54t=342
114t=342
t=342/114
t=3 hours ans.
Proof:
60*3+54*3=342
180+162=342
342=342