A train went 300 miles from city X to city Y at an average speed of 80 miles per hours ( mph ). At what speed did the train travel on the way back if its average speed for the whole ( both ways ) trip was 100 mph? | Prostuti
1. A train went 300 miles from city X to city Y at an average speed of 80 miles per hours ( mph ). At what speed did the train travel on the way back if its average speed for the whole ( both ways ) trip was 100 mph?
