Respuesta :
if dey al differnt mice then
9 choices for first mouse
8 for 2nd (1 less)
7 for 3rd choice
so
9*8*7=504 ways to choose 3 mice
9 choices for first mouse
8 for 2nd (1 less)
7 for 3rd choice
so
9*8*7=504 ways to choose 3 mice