2. Because there are 13 cards of various colors in 52 cards, which is equivalent to choosing your own color from these 13 cards, it is C( 13,5), C (13,3), C (13). Divide by 13 cards randomly selected from C(52 playing cards), and it is C(52 13).

Extended data:

1, the probability is also called "probability". It reflects the measure of the probability of random events. Random events refer to events that may or may not occur under the same conditions.

For example, it is a random event to randomly select one from a batch of goods with genuine products and defective products, and "what is extracted is genuine products". Suppose a random phenomenon is tested and observed n times, in which event A appears m times, that is, its frequency is m/n. After a lot of repeated experiments, m/n is often closer to a constant. This constant is the probability of the occurrence of event A, which is usually expressed by P (A).

2. The first person to calculate probability systematically was cardano in16th century. This is recorded in his book. The content of probability in the book was translated from Latin by Gould.

3. The word "probability" comes from the Latin word "probability itas" and can also be interpreted as "integrity". Integrity means "integrity and honesty". In Europe, integrity is used to express the authority of witness testimony in court cases, which is usually related to the reputation of witnesses. In short, it is different from the meaning of probability "possibility" in the modern sense.

References:

Baidu Encyclopedia: Probability