Question

Two trains 500 miles apart accidentally are on the same track heading toward each other. The passenger train is traveling 80 mph while the freight train is traveling 40 mph. A dispatcher discovers the error and warns them 1 minute before they were to collide. How far apart, in miles, were they when they were warned?

Answer 1

2 miles

Explanation:

Their combined speed (speed of closure) is 80 mph + 40 mph = 120 mph.

120 mi/h = 120 mi/(60 min) = 2 mi/min

The distance between the trains at the 1-minute mark is ...

(1 min) · (2 mi/min) = 2 mi

They were warned when two miles apart.