Question

If M and N are any two events, the probability that at least one of them occurs is

A. P (M) + P (N) – 2 P (M ∩ N)
B. P (M) + P (N) – P (M ∩ N)
C. P (M) + P (N) + P (M ∩ N)
D. P (M) + P (N) + 2P (M ∩ N)

Answer 1

Given that M and N are two events,

By General Addition Rule,

P(A ⋃ B) = P(A) + P (B) – P(A ⋂ B)

∴ P(M ⋃ N) = P(M) + P(N) – P(M ⋂ N).

Hence, the correct option is (B).