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A complete collection of probability formulas in junior high school mathematics
(1) gets the red ball for the second time, that is, "1 gets the white ball and gets the red ball for the second time", and the probability is 2/3x 1/2= 1/3.

(2) Algorithm 1: 1-P (twice getting white balls) = 1-2/3x 1/2=2/3.

Algorithm 2: p (red ball) =P (red ball for the first time 1 and white ball for the second time) +P (white ball for the first time 1 and red ball for the second time) = 2/3x 1/2 = 2.

To sum up, the probability of getting the red ball for the second time is 1/3, and the probability of getting the red ball is 2/3.

Please adopt it, thank you!