Interest rate swap and comparative advantage theory

Hi,
I had some confusion about comparative advantage theory. In Question 1 – June 2014 exam, when CMC Co can borrow at 2.2% fixed rate or LIBOR + 0.4% (floating rate), the Counterparty can borrow at 3.8% fixed rate or LIBOR + 0.8% (floating rate).
Why did the examiner conclude that “CMC Co has a comparative advantage in borrowing at the fixed rate and the counterparty has a comparative advantage in
borrowing at the floating rate.”?
One more question, Can you explain to me more detail about the rule of calculate swap fixed rate and swap floating rate ( ie2.4% and Yield rate in the answer of question 1 June 14)
Thanks in advance,
HV