Redo the preceding question, supposing that the system capacity is infinite and that
(a) only the potential type I customers are willing to wait until being served (those of type II go away if the assistant is busy),
(b) only the potential type II customers are willing to wait until being served (those of type I go away if the hairdresser and her assistant are busy),
(c) all the potential customers are willing to wait until being served.