Probability Formulas:

P(AB)=P(A)+P(B)P(AB)P(Ac)=1P(A)P(B)=P(AB)+P(AcB)P(A \cup B) = P(A) + P(B) - P(A \cap B) \\ P(A^c) = 1 - P(A) \\ P(B) = P(A \cap B) + P(A^c \cap B)