"There are hers and yours."
Translation:Il y a la sienne et la tienne.
In such a sentence "hers" and "yours" refer to the same thing/object, for instance: her husband and your husband(s) or her dress and your dress(es), etc.
Therefore, you have to pair the genders in your translation, remembering that French possessives agree with the possession and give no indication of the owner's gender.
- le sien et le tien/vôtre
- la sienne et la tienne/vôtre.
The only mix you can use is singular/plural because "hers" and "yours" do not tell us how many objects are concerned per owner:
- le sien et les tiens/vôtres
- la sienne et les tiennes/vôtres
- les siens et le tien/vôtre
- les siennes et la tienne/vôtre
Yes, context would shed light on the owner's gender.
- Voici ton stylo (masc. sing.) et celui de ta soeur == le tien et le sien
- Il y a tes chaussettes (fem. plur.) et celles de ta soeur == les tiennes et les siennes.
In the above examples, we still don't know the gender of the person spoken to with "ton/tes". Yet, with "tu" we know it is one person (vs vous/you).
Everywhere in the course "il y a" translates to "there is/are" and vice-versa.
The reason is that "il y a" is just stating the presence of something somewhere. It is quite vague.
"Voici/voilà" are much more precise. Remembering that "voici/voilà" actually mean "see here/see there", you can tell for yourself that with those 2 words, you are more emphatically pointing out something or someone.
As a consequence, only "here is/are" is translated to "voici/voilà" and vice-versa.
There's no way of knowing in either language. The reason that the pronouns sienne and tienne are feminine is due to the gender of the objects that 'you' and 'she' own. Now, of course, in this exercise the objects are not known, and the English sentence could just as easily translate as: "Il y a le sien et le tien", where the pronouns stand in for a masculine object, similarly unknown due to lack of context.
If this is confusing, remember this is no different to how possessive adjectives work in French. You don't say "mon mère" even if you're male; you say "ma mère" because your mother is female, and mère is a feminine noun.
"Il y a" is used to mean and translate "there is" or "there are".
- There is an apple = il y a une pomme
- There are apples = il y a des pommes.
"ce sont" means and translates to "they are" or "these are" or "those are".
- They are my parents = ce sont mes parents
- These are apples = ce sont des pommes
- Those are apples = ce sont des pommes.