Webthe birthday problem (also called the birthday paradox) deals with the probability that in a set of n n randomly selected people, at least two people share the same birthday. Webthe correct answer, according to the birthday paradox, is just 23. The birthday paradox is a probability theory that states that the probability for two people to. Webit’s the probability of the first two having different birthdays, and the probability of the third person having a different birthday that either of those first two.