This is an example of exchange theory.
In sociology, exchange theory has to do with maximizing benefits while also minimizing costs. When applied to Bill and Cathy's situation, they are taking advantage of each other's skills in order to minimize costs - Bill can cook and Cathy can't (so they can prepare food on their own) and Cathy can repair stuff and Bill can't (so they don't have to get a handyman).
Answer:
The goal of success is shared by a majority of people, but not everyone has equal means for achieving that goal.- D.
Compromise is important in democracy as it ensures that no side will stalemate, it is Suffrage