Final answer:
No, the friend is not correct. Mutually exclusive events are events that cannot occur at the same time. The probability of one event happening given that the other event has occurred is always zero.
Step-by-step explanation:
No, the friend is not correct.
Mutually exclusive events are events that cannot occur at the same time. If two events are mutually exclusive, the probability of one event happening given that the other event has occurred is always zero. In this case, P(H | J) would be equal to 0, not 20.
To understand this, you can think of a Venn diagram. Since H and J are mutually exclusive, their circles would not overlap, meaning there would be no common space for both events to occur together. Therefore, the probability of event H happening given that event J has occurred is zero.