Probability of relatively independent events in Mathematics There are 10 balls from No.0 to No.9, which are pulled out one at a time and then put back. The probability of pulling 1 is 1 / 10, that is to say, there will be one in 10 times. Then I want to know the probability of pulling 1 only after 20 times and how much is it after 30 times
20 times 1 / 10 * (9 / 10) ^ 19 times 30 times 1 / 10 * (9 / 10) ^ 29