Given the four digits 2, 4, 6, and 7, how many different positive three-digit integers can be formed using these digits if a digit may not be repeated in an integer?
2, 4 , 6, 7
We can choose any 3 of 4 = C(4,3) = 4
This will form 4 different sets with 3 elements each and permuting these = 3! = 6
So
4 * 3! = 24 integers
