Probability Rules

P(A and B) = P(A) × P(B) (independent events). P(A or B) = P(A) + P(B) − P(A and B). P(not A) = 1 − P(A). P(neither) = (1-P(A)) × (1-P(B)).

Event Probabilities

P(A) - between 0 and 1
P(B) - between 0 and 1

Results (Independent Events)

P(A and B)
0.20
P(A or B)
0.70
P(not A)
0.50
P(not B)
0.60
P(neither A nor B)
0.30
P(exactly one)
0.50