Final answer:
In probability, the probability of mutually exclusive events occurring together is 0, while for independent events, it is the product of their individual probabilities.
Step-by-step explanation:
The question deals with the concept of probability in Mathematics. When two events are mutually exclusive, the probability of both events occurring together is zero. Given P(H) = .25 and P(D) = .15, and knowing that H and D are mutually exclusive, the probability of both events, P(HD), is 0 because they cannot happen at the same time. This is supported by the provided information in reference 72, thus the correct answer is B. 0.
Regarding independent events, if P(A) = .2 and P(B) = .3 and they are independent, then the probability of A and B occurring together, P(A AND B), is found by multiplying their individual probabilities: P(A AND B) = P(A)P(B) = (0.2)(0.3) = 0.06. The correct answer to this is referenced in exercise 70, thus the answer is D. .06.