"The hospital employs eleven people."
Translation:Szpital zatrudnia jedenaście osób.
In plural they seem more or less interchangeable, although technically "osób" means "persons".
Ahh okay. I tried to use ludzi but it won't accept it. So just curious. Thx for the reply
Because it's wrong grammatically. "ludzie" takes either a collective numeral (jedenaścioro ludzi) or the masculine personal form (jedenastu ludzi). Added both now. The second option would actually mean that all of them are guys, you just decided to use "people" instead of "men".
"osób" in plural is simply... easier in usage. That's why it's more common with numerals.