I have to write the sentence:
En chemin, elle rencontre un loup qui a faim.
in the past. Should I translate to "elle a rencontré" or "elle a rencontrée" and why?
En chemin, elle a rencontré(e) un loup qui avait a faim.
the always valid rule is that with avoir for auxiliary, there is no agreement, as opposed to être. Here, a is from avoir, therefore no need to agree. But be careful, because if she met a feminine noun and you want to specify this, you could also say
Meaning 'she met her', in which case you have to agree the ending. Because the "l'" is a complément objet direct (COD) placed before the verbal phrase, and if there is a COD before avoir used as an auxiliary you have to agree the verb with it. Similarly « Elle les a rencontrées » if she met a group of feminine things.
"Elle a rencontré" is correct, because agreement with the past participle is only used when