Answer:
Time taken by train in onward journey = 12 hours.
Step-by-step explanation:
Given:
Speed of train making a trip to a repair = 25 mph
Speed of train on return trip = 20 mph
Time taken for return trip = 15 hours
To find the time taken on the on wards trip.
Solution:
The distance traveled by the train on the trip and return trip is the same as the y are of same trips in opposite directions.
Distance can be calculated by using the data for the return trip.
Distance= 
Distance= 
Speed of train for on ward trip = 25 mph
Time taken = 
Time taken = 
Thus, time taken by train in onward journey = 12 hours.