Suppose there are 15 rooms among which a person in present in one room. If i pick 5 rooms out of them, what is the probability that the person is present in one of the 5 rooms selected?
No of ways we can pick 5 rooms: 15C5, So answer could be x/15C5
Where am i stuck is how to figure out x? Among 15C5 selections, which of them will contain that specific room in which the person is there?