Final answer:
To find P(A ∪ B), use the formula P(A ∪ B) = P(A) + P(B) - P(A ∩ B), then substitute the given values to get the answer.
Step-by-step explanation:
To find P(A ∪ B), we can use the formula P(A ∪ B) = P(A) + P(B) - P(A ∩ B). Given that P(A) = 0.25, P(B) = 0.40, and P(A ∩ B) = 0.10, we can substitute these values into the formula.
P(A ∪ B) = 0.25 + 0.40 - 0.10 = 0.65.
Therefore, the correct option is D. 0.65.