A credit-rating agency assigns ratings to corporate bonds. The agency rates bonds offered to companies that are most likely to honor their liabilities AAA. The ratings fall as the company becomes more likely to default, dropping from AAA to AA, A, down to BBB, BB, B, CCC, CC, R, and then D (for in default). Let the event W = {AAA, AA, A, BBB, BB, B} and V = {BBB, BB, B, CCC, CC}.
(a) Find the intersection W and V.
(b) Describe the union W or V.
(c) Find the complement (W or V)c.