Answer:
On the way out the train traveled at about 40 mph, while on the return it did so at 20 mph.
Explanation:
Since an empty freight train traveled 60 miles from an auto assembly plant to an oil refinery, and there, its tank cars were filled with petroleum products, and it returned on the same route to the plant, and the total travel time for the train was 4.5 hours, if the train traveled 20 mph slower with the tank cars full, to determine how fast did the train travel in each direction the following calculation must be performed:
60/20 = 3
60/40 = 1.5
60/20 = 3
3 + 1.5 = 4.5
Therefore, on the way out the train traveled at about 40 mph, while on the return it did so at 20 mph.