Probability theory assumes that there is a 5 white ball and 3 black balls in the bag. Take one ball at a time and never put it back, and take it from the bag six times in a row. What is the probabilit

Probability theory assumes that there is a 5 white ball and 3 black balls in the bag. Take one ball at a time and never put it back, and take it from the bag six times in a row. What is the probability that the black ball will eventually be taken out? The answer is 3/8, and the probability of taking it out is the same every time.

You can think of it this way: the original question is equivalent to the full arrangement of eight positions, and the sixth is the probability of black ball.

So it is C( 1, 3) a (7,7)/a (8,8) = 3/8, and the same probability can be obtained every time.

The same type (that is, the same method of consideration) also has the problem of drawing lots, and the probability of drawing lots is the same whether drawing lots first or drawing lots later.