Erratum in Level 3 Spanish mini story: Historia 45

In the Spanish mini story, Historia 45, the phrase “por tres días” is used to mean “for three days”. I am only a beginner, but I was under the impression that “por” was a false friend here and that correct would be to use “durante tres días”. Does anyone know whether “por tres días” is correct? The full sentence is: “Juan ha estada escalando las montañas por tres días”

“Por tres días” is absolutely correct, it’s a variant of “durante tres días”. Depending on the speaker/country, one expression or the other may be more usual

Muchas gracias