Question

(大学概率题)设有3枚金币,6枚银币,分别装在3个盒子中(每盒3枚),求恰好每盒都是1枚金币2枚银币的概率.

Answer 1

ABB ABB ABB

{(C3 1)(C 6 2)(C 2 1)(C 4 2)}/{(C9 3)(C6 3)}

=(45*12)/1680

=9/28

或者

{3!/(1!1!1!)*6!/(2!2!2!)}/{9!/(3!3!3!)}

=9/28