“randomly”，所有数学上的概率问题大前提都是Randomly picking

所有跟帖： 

• We only care the result after it becomes a fact -flagsix- ♂ (0 bytes) () 05/19/2020 postreply 07:34:01

• The only fact is u know the 1st one is white -姜申- ♂ (0 bytes) () 05/19/2020 postreply 07:39:53

• but u don't know where it came from. That's the whole point -姜申- ♂ (0 bytes) () 05/19/2020 postreply 07:40:39