There's two trains going opposite directions, ones going 50 mph and the other 60 mph, in 90 minutes how far are these trains going to be? (in mphs)

guess you actually want the distance in miles
assuming they start at the same point (side by side rails) their distance increases at a rate of 50+60 = 110 mph
so after 90 mins = 1 1/2 hours they are 165 miles apart