"that slows its speed to of its average speed up to the time of the failure"
something missing here.
One hour out of the station, the locomotive of a freight train develops trouble that slows its speed to of its average speed up to the time of the failure. Continuing at this reduced speed it reaches its destination two hours late. Had the trouble occurred 50 miles beyond, the delay would have been reduced by 40 minutes. Find the distance from the station to the destination.
2 answers
its speed to 2/5 of its average speed up to the time of the failure.