When Present Perfect and Preterite are both acceptable options

Question

Mis amigos y yo ________ juntos durante un mes.My friends and I were able to travel together for a month.(HINT: It refers to a past action)
Since both the Present Perfect "hemos podido viajar" and Preterite "pudimos viajar" are correct for this question (it is both limited to a set past time period and the speaker is obviously involved in the action), shouldn't the lesson explain that sometimes both options are acceptable?

Answer

Hola JeraldDespite the lesson talking about when we use one or the other tense, the test-questions are set without any distinction. In this example for example you can use both because you can consider that "you and your friends were together during a month" seeing this time as finished and disconnected from now, the moment of speaking (pudimos viajar), or you can see it as "you and your friends have been together during a month" in a scenario where it's not relevant when this started and ended, the time is not important, so it's a more general statement. (hemos podido viajar) - they are both past actions but we're not considering nuances. I hope it clarified it.Saludos