If P (A ∪ B) = P (A ∩ B) for any two events A and B, then
A. P (A) = P
B. (B) P (A) > P (B)
C. P (A) < P (B)
D. none of these
P (A ∩B) = P (A U B)
Now, P (A U B) = P (A) + P (B) – P (A ∩ B) ……. (by general addition rule)
P (A ∩ B) = P (A) + P (B) – P (A ∩ B)
Thus, [P (A) – P (A ∩ B)] + [P (B) – P (A ∩ B)] = 0
Now,
P (A) – P (A ∩ B) ≥ 0
& P (B) – P (A ∩ B) ≥ 0
P (A) – P (A ∩ B) = 0
P (B) – P (A ∩ B) = 0
Thus, P (A) = P (A ∩ B)
& P (B) = P (A ∩ B)
Therefore, we get
P(A) = P (B)
Thus, option A is the correct answer.