Leur carriere vs. leurs carrieres

Question

I wrote, "leurs carrieres" since the speaker is describing several actresses and their careers, but this was marked wrong. 
I redid the lesson, (link below), which covers this subject, and there are several examples including: "leurs parents" and "leurs chaussures". It seems that this issue has come up in the discussions before, but I am still not clear as to when to use the plural form and when to use the singular form when referring to more than one person and their possessions. Using the singular form makes it sound, (to me anyway), as if these actresses have all shared the same career. 
 
Notre/nos/votre/vos/leur/leurs = our/your/their (French Possessive Adjectives)
 
I appreciate any help on this matter. Otherwise, it was fun to learn all about Aissa Maiga. I will certainly google her!
Bonne Continuation !

Accepted Answer

Bonjour N. Hilary,
We're glad you enjoyed the content of this exercise. It's nice to have such a lovely feedback!
In French, with "leur" or "leurs", you tend to take the position of the individual - which implies using of the singular form  - whereas in English, you tend to look at the entire group, and therefore, use the plural form.
So, in this exercise, the actresses have "one career" each (each have a different career), therefore, you will use "leur".
Take a look at my previous answer below:
Does the translation match up for “leur lettre”, or should it be “leurs lettres”?
I hope this is helpful.
Bonne journée !