A classic counting problem is to determine the number of different ways that the letters of "occasionally" can be arranged. Find that number

Answer 1

2x O, 2xa 2xc 2xl;

singletons are S, I, N, Y

12! / (2! 2! 2! 2! (12-2-2-2-2)!)

12! / ( 2! 2! 2! 2! 4! )

4! cancels; 2!=2

12*11*10*9*8*7*6*5 / (2*2*2*2)

2 cancels:

6*11*5*9*4*7*3*5 =

1,247,400