Final answer:
To represent the wagon failures, the proportion 20/500 = 25/625 can be used.
Step-by-step explanation:
To represent the wagon failures, we can use the proportion 20/500 = 25/625. This proportion is formed by comparing the number of wagons that failed inspection (20 in June and 25 in July) to the total number of wagons inspected (500 in June and 625 in July).
Learn more about Proportions in Mathematics