Harry Potter and Ron Weasley need to get to Paddington station as quickly as possible since the Hogwarts Express leaves from platform in 19 minutes. If they were to both run, they would get to the station in only 25 minutes.
However, by a stroke of luck, one of them has a broom, which, alas, can only carry one person at a time. The broom can fly twice as fast as one of the boys can run. But this is an old, cheap broom: it cannot fly by itself. Either Harry or Ron must sit on the broom, and the other must run.
Can they catch the train?
Details and Assumptions:
They are only in their second year, so they can't Apparate.
Keep to the constraints of the problem. The broom can't be snapped in half.
Bonus points for spotting a Harry Potter mistake in the question.