A freight train leaves a station traveling 60 miles per hour

A freight train leaves a station traveling 60 miles per hour. Thirty mintues later a passenger train leaves the station in the same direction on a parallel track at a speed of 72 miles per hour. How long will it take the passenger train to catch the freight train?
I either get 42 mintues or 75 minutes not sure.

Solution

train A is 30 miles ahead of train B
B is overtaking A at 12 mph
30/12=2.5 hrs=2 hrs 30 min