将6个编号是1至6的小球放进编号为1至6的六个盒子中,则球编号与盒子号不

2025-05-09 20:47:45
推荐回答(1个)
回答1:

A(6,6)-C(6,1)×A(5,5)+C(6,2)×A(4,4)-C(6,3)×A(3,3)+C(6,4)×A(2,2)-C(6,5)×A(1,1)+C(6,6)
=720-720+360-120+15-6+1
=250,
有250种排列