Final answer:
Without specific numbers or context, a precise response cannot be given to the student's question regarding attendance and probability. However, the question likely relates to concepts in set theory and probability in mathematics.
Step-by-step explanation:
The student's question seems to involve determining the number of individuals in a group who are planning to attend different events, as well as calculating probabilities based on given attendance information. After reviewing the provided reference information, it appears that the student may be interested in understanding concepts related to set theory and probability. However, due to the nature of the reference excerpts and multiple potential interpretations without further context, a precise response involving step-by-step explanation cannot be given. It is recommended to provide more details or clarify the question for an accurate answer.