Second, the probability that the first student catches "1" is 25%, so when he catches a paper ball, there will be two results: "1" or not "1". If "1" is caught, there is no need to draw lots. The class representative has been selected, and the probability that the next three students catch "1" is zero. Is this unfair to the last three students? But if you don't catch "1", there are still three paper balls left, and the possibility that the second student catches "1" is 1/3, which is unfair.
The third type: the possibility of feeling the first feeling is the same, both of which are 25%. Because the possibility is 25%, we usually solve the problem by drawing lots. Because of fairness, everyone agrees. But I can't explain it clearly.
Is the 25% probability of the first student comparable to the 1/3 probability of the second student? When you think about it, it's really unparalleled. They have different units of "1". The first student's "25%" is 4, while the second student's "1/3" is 3. That's the original problem, so can we unify the unit "1"? For example, if the second student catches three paper balls, which is 3/4 of the original four paper balls, then the possibility that the second student catches "1" is that 1/3 of the original four paper balls, and 3/4 of 1/3 is not exactly 1. It seems that the possibility of the second student catching "1" is the same as that of the first student.
The probability of being caught first is: 1/4=25%.
The second probability is: 3/4* 1/3= 1/4=25%.
The third probability is: 2/4* 1/2= 1/4=25%.
The fourth probability is:1/4 *1=1/4 = 25%.
It is also possible to catch four.
To sum up, the probability is the same. So the first and last possibilities are the same.
Hope to adopt ~ I'm doing it too ~