How to calculate the probability of four people taking apples? Please calculate the method in detail

First of all, it is necessary to set that the game can only be settled after the autumn, that is, it cannot be cashed immediately after the lottery, and it should be cashed after 100 people draw lots, otherwise there will be more and less in the middle, and there will be no apples in the basket, so the game has to be interrupted.

Set four labels: A, B, C and D (take 10, 20, 30 and put 10 respectively).

Since you want all four labels, you can't be short of one. Let ABC have 1 apple each. In order to keep the number of apples in the basket unchanged, D should have 6 apples, (6* 10= 10+20+30). So there is 3* 1+6=9, plus B 1, D2, (20=2* 10), and the number of signatures is *** 12. In the future, increase 1 every1a.

Now, we add four A's and four D's to the above 12 to make 20, namely A5, B2, C 1 and d 12. (The number of apples remains unchanged: 5 * 10+2 * 20+ 1 * 30 =

This is just one of the schemes, and there are many others.