Translation:
The Peruvian novelist is in the student residence.
¿Le sirvo pastel a usted? Sí sírvamelo.
I believe it was Fidel Castro!
Hola!
You can tell which article to use by looking at the ending of the noun in the sentence, for example, mochila the ending is feminine singular -a, therefore, the corresponding article is La. La mochila <span>es grande.</span>