Translation:The bus will arrive at the station in fifteen minutes.
It's A normal way. is going to arrive, is arriving. arrives and will arrive could and probably would all be used pretty much interchangeably. There are some VERY VERY subtle differences in connotation. But I'm sticking with will for this skill because I'm betting that Duolingo has translated most of these as will instead. Question - can the future be indicated in Spanish by the use of an adverb or preposition of time in the sentence, as we do in English, without using either ir + inf or future simple? ( llego en cinco minutos)