When is symmetric vs asymmetric the "right" answer on exams?

Mental model: asymmetric solves the "we've never met" problem (key exchange, signatures, identity); symmetric does the bulk work once a shared key exists. Real systems use both — asymmetric to agree on a symmetric key, then symmetric for the data. On exams, "establish trust between strangers" = asymmetric; "encrypt a lot of data fast" = symmetric.